# Hot Math Posts

### How To: Convert Fahrenheit to Celsius with a formula

In order to convert Celsius to Fahrenheit, you will need to use this formula: F = 9/5C + 32. Therefore, you will need to solve for C or substitute values and solve in that manner.

### How To: Find the slope of a line given 2 points with fractions

In this video tutorial the instructor shows how to find the slope of a line given two points with fractional values. To do this first name your two points as point 1 with coordinates as x1, y1 and point 2 with coordinates x2, y2. Then substitute the values in the equation of the slope which is slope m = (y2 - y1) / (x2 - x1). Now all you have to do is simply the fraction after substituting the point values. Be careful about the signs while substituting in the formula. Now finally after solvin...

### How To: Do long division with decimals

Video Nerd thinks that when your doing long division with decimals you should first take out the decimal. Write the number as if it didn't have a decimal. For example if the problem was 12.5 divided by 5 then you will just use 125 and divide that by 5. Next divide the first digit of the dividend by the divisor an write the number up top. Next you multiply, after your done multiplying the numbers subtract, and when your done subtracting the numbers drop the reaming numbers in the dividend down...

### How To: Find the Volume of Composite Figures (Also Called Composite Shapes)

Composite figures are composed of several geometric shapes and are three-dimensional shapes. The first composite shape is a combination of a rectangular prism and a pyramid. To find the volume of the entire shape you find the volume of each individual shape and add them together. The second figure consists of a cylinder and a hemisphere. Check out the video below for the full lesson.

### How To: Use derivatives to find slope in calculus

Need help figuring out how to work with derivatives in calculus? From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test). With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to use derivatives to f...

### How To: Solve equations with the order of operations

In mathematics, the order of operations define the priority in which complex equations are solved. The top priority is your parenthesis, then exponents, followed by multiplication and division, and finally addition and subtraction (PEMDAS). This video tutorial demonstrates the order of operation with various examples and explains the associated methodology. From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autod...

### How To: Divide small numbers by big numbers

This is a mathematical educational video on how to divide a small number by a larger number. You are aware that it is easy to divide a larger number by a small number. For example, if you want to divide 379 by 9 it is easy to do so. But if you have to divide 9 by 379 it is a bit difficult. You have to add a zero and see if you can divide. You need to add one more zero so that you can divide 900 by 379. But you should know that the answer would start like this 0.0 as we have added 2 zeros alre...

### How To: Find extra points for a parabola (quadractic equation)

This is a mathematical educational video on how to find extra points for a parabola. In the first two examples there is no need for finding extra points as they have five points and have zeros of the parabola. In example 3 we need to find extra points. The equation is y=4xsquare-4x+4. You can take x= -1 and get the value for y. You will get a point now. Similarly you can substitute -2 for x in the same equation and get the value for y. Now you get another point. Now you can draw the parabola.

### How To: Determine the age of a fossil using carbon-14

If you have a fossil, you can tell how old it is by the carbon 14 dating method. This is a formula which helps you to date a fossil by its carbon. If a fossil contains 60% of its original carbon, how old is the fossil? The half life of carbon 14 is 5600 years. That means this is how long it takes for half the nuclei to decay. After 5600 years, if we start with a gram, we end up with half a gram. This rather complex formula shows you how to solve this puzzle using accepted scientific methods.

### How To: Multiply & Divide Numbers (Basic Elementary Math)

Adding and subtracting may be the easiest of mathematical operations, but once you get it down, multiplication and division can be just as easy. That's why it's called elementary arithmetic. If it were harder, it would be called college algebra or trigonometry. But it's not— it's basic math, and once you get your head around the numbers, you'll never hate math class again! (Okay, maybe you will.)

### How To: Find the Slope Given 2 Ordered Pairs

Slope is the change in Y over the change in X. Written out, the formula looks is as follows: (y2-y1)

### How To: Find a slope of a line parallel/perpendicular to it

This video tells you how to find a slope of a parallel / perpendicular to it. In the equation y = mx + c, m is the slope. To calculate the slope of a line that is parallel to another line, you have to consider the rule m1 = m2 which means slope of the first line m1 is equal to the second line m2, if both the lines are parallel. Take the equation y = 2/3x - 7.2/3 is the slope. According to the rule m1 = 2/3 and so m2 = 2/3.Now to calculate the slope of perpendicular line you have another rule ...

### How To: Simplify a quadratic formula result

In this video the tutor shows how to simplify a quadratic formula result. You can solve a quadratic equation using the quadratic formula. The first thing you have to do when given the quadratic equation is bring all the terms to one side so that you have a zero on the other side of the equals to sign. Now the formula to calculate the roots of the quadratic equation ax*x + bx + c = 0 is x = (-b + root of(b*b - 4*a*c) ) / 2 * a. The other root can be obtained by using the minus sign before the ...

### How To: Find measure of an exterior angle of a regular polygon

This tutorial the shows how to find out the measure of an exterior angle of a regular polygon. He shows the formula to find it which is 360/n, where n is the number of sides of the regular polygon. He goes on further to explain the formula by taking an 18-sided regular polygon as example and computes its exterior angle as 360/18, which is 20 degrees. If you are looking to compute the exterior angel of a regular polygon, follow the procedure given in this tutorial.

### How To: Find the coordinate of a point

In this video the author shows how to plot a point on the coordinate plane. He explains about the coordinate plane and shows how to read and write points to it with an example. He says that any point on the coordinate plane has an x, y- coordinate values. He says that for any point its projection on the x-axis is its x-coordinate and the points projection on y-axis is its y-coordinate. He shows how to find this out for a sample value and plots the coordinates of it. In this video the author u...

### How To: Calculate square roots on paper the easy way

Perhaps not as easy as using a calculator, but easy nevertheless! With mathematics, as with anything else, not everyone progresses at the same rate. Happily, in the age of Internet video tutorials, this isn't a problem. Those who progress quickly can go beyond what's being taught them and those who are struggling likewise have all the time in the world to catch up. With this free video math lesson, you'll learn how to find square roots by hand.

### How To: Rationalize square roots

In this tutorial, we learn how to rationalize square roots. You cannot have square roots in the denominator of an equation. You need to multiply so the square root goes away. You can do this by multiplying the top and bottom of the equation by the bottom denominator. From here, this will make the square root go away, so your equation will be normal numbers. After you have done this, you will have the equation answered and you will be able to simplify it to find the end answer. You can do this...

### How To: Find the equation of a circle given: center & tangent

In this video, the instructor shows how to find the equation of a circle given its center point and a tangent line to it. To do this, take a graph and plot the given point and the tangent on that graph. Now, from the center of the circle, measure the perpendicular distance to the tangent line. This gives us the radius of the circle. Using the center point and the radius, you can find the equation of the circle using the general circle formula (x-h)*(x-h) + (y-k)*(y-k) = r*r, where (h,k) is th...

### How To: Identify characteristics of a sample during a survey

To identify characteristics of a sample in your survey, there are many factors to consider of your samples. The first four characteristics you need to focus on are gender, age, income level, and education level. All four of these characteristics must be proportional to that of the population. You also need to consider the geographic location. Only take samples from the immediate geographical area. Finally, an important characteristic of the survey is the sample size. You do not want to ask to...

### How To: Calculate the height and volume of a pyramid

Need to know how to calculate the height and volume of a pyramid in geometry? Learn how with this free video lesson. From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test).

### How To: Find standard deviation

In this video tutorial, viewers learn how to calculate the standard deviation of a data set. The standard deviation of a statistical population, a data set, or a probability distribution is the square root of its variance. To calculate the standard deviation, users will need to follow these steps. 1) Find the mean of the data. 2) Subtract the mean from each data point. 3) Square each of the values you got in step 2. 4) Then find the mean of the values you get from step 3. 5) Finally, square r...

### How To: Solve word problems containing radical equations

See how to unpack and solve a word problem containing radical equations with this free video math lesson from Internet pedagogical superstar Simon Khan. From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test).

### How To: Find the value of a variable in an algebraic equation

Need help figuring out how to solve simple algebraic equations? Learn how with this free video lesson. From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test).

### How To: Complete a proof involving segments

This video from Yay Math! is a geometry lesson on how to complete a proof involving segments. He draws a line segment with four points labeled A, B, C and D. The problem is as follows: Given: AC is equivalent to BD. Prove that AB is equivalent to CD. The first statement of proof is the given. Next, you need to define the congruent segments and state that they're equal in measurement. Next, break down the segments: AC=AB+BC, and BD=BC+CD. This is called segment addition postulate. The end of t...

### How To: Graph half an ellipse

If you are given an equation of ellipse in the form of a function whose value is a square root, you may need to simplify it to make it look like the equation of an ellipse. Now equate the function to a variable y and perform squaring on both sides to remove the radical. Now simplify the equation and get it in the form of (x*x)/(a*a) + (y*y)/(b*b) = 1 which is the general form of an ellipse. Now you will have the x and y intercepts which are a and b respectively. Using this values graph the eq...

### How To: Find how many toothpicks will be needed to form the nth figure in a sequence

From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps. With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to employ inductive reasoning to determine the number of toothpicks you'll require to generate the nth (e.g., the 50th) figure in a sequence of figures.

### How To: Find the surface area of a cylinder easily

In this video tutorial the author shows how to find the surface area of a cylinder. He shows a four step approach to solve this problem. First he gives us a formula to find the surface area of a cylinder, where Surface area A = 2 * Pi * R * R + 2 * Pi * R * H, where R is the radius of the base of the cylinder and H is the height of the cylinder. Now he identifies those values and substitutes them in the formula giving the surface area of the cylinder. This video shows how to compute the surfa...

### How To: Simplify radicals which are not perfect squares

Need help reducing radical expressions without perfect square or cube roots? Take heart: this free math lesson will ensure that you know everything you need to know for that next big test. Examples include square roots, cube roots, and 4th roots. You'll also learn a technique to simplify n-root expressions as well as how to simplify variables in radical expressions.

### How To: Find a missing part of a triangle, similar to another

In this tutorial the author shows how to find out the missing part of a triangle that is similar to another triangle. He explains the concept of similar triangle diagrammatically by showing that similar triangles have similar angles and parallel sides. Now he labels sides of similar triangles and marks the value of unknown side as variable x. Now in similar triangles as the lengths of sides of proportionate he shows how to write a equation of proportion and solves it finding the missing part ...

### How To: Figure out the domain & range of a piecewise function

Need to calculate the domain and range of a graphed piecewise function? Learn how with this free video lesson. From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test).

### How To: Find the formula of a piecewise function given a graph

This video shows how to find the formula of a piecewise function when given a graph. The first step is to write a definition for the graph, which is done by identifying the different domains shown in the graph. The second step is writing formulas for each domain specified by the lines in the graph. The point-slope formula is used to identify the slope and y-intercept for the leftmost domain, which has a sloped line. A point and horizontal line make for simpler equations in the other pieces of...

### How To: Evaluate logarithms using a calculator TI-83

A video to help calculator users find the natural logarithm (log base e, or "ln") and standard logarithm (log base 10, or simply "log") of any number using a TI-83 calculator (works for any issue of the TI-83 calculator or even a TI-84 calculator). Turn on your calculator. To find the natural log of a number, press the "ln" button (the third button from the bottom left), enter the number you want to find the natural log of, press the ")" (closed parenthesis) button, then press enter. The same...

### How To: Calculate the circumference of a circle

This video shows how to calculate the circumference of a given circle. The video first describes the circumference or perimeter of a circle as the distance around the outside of a circle. To find the circumference we need either the radius or the diameter of the circle. When you know the diameter of the circle, the formula to find the circumference denoted by 'C' is 'pi' times the diameter, where 'd' is the diameter and 'pi' is a constant, the approximate value being 3.14. And when you are gi...

### How To: Calculate the area of a parallelogram

Calculating The Area Of A Parallelogram A parallelogram is a 4-sided shape formed by two pairs of parallel lines. Opposite sides are equal in length and opposite angles are equal in measure. To find the area of a parallelogram, multiply the base by the height. The formula is:

### How To: Calculate probability in "at least one" problems

Calculating probablities can be used to help us make decision. PatrickJMT explains how to calculate probability in an "either A or not A" scenario. The probability of A plus the probability of not A is equal to one. Therefore, the probability of A is equal to one minus the probability of not A ; P(A)= 1 - P(not A). The probability of a major earthquake in San Francisco over a period of time is used as an example. The probablity of an earthquake of a magnitude of 7.5 or greater in San Francisc...

### How To: Derive the basic area of a triangle

In this video tutorial, viewers learn how to solve the area of a triangle. The formula for the area of a triangle is A = ½ x b x h or bh/2. The base of the triangle is always at the bottom; it is the side that the triangle sits on. The height is the length between the base and the highest point of the triangle. Multiply the base and height of a triangle; then divide by two or multiply by half. The measurement unit of the answer should be squared. This video will benefit those viewers who need...

### How To: Use a mean and scatter plot for Statistics

Wondering how to use a mean and scatter plot for statistics? Just follow the few simple steps as below.

### How To: Do normal probability calculations on a calculator

Probability computation is a complex process and even using a calculator can be difficult. But normal probability calculations can be performed quickly with the help of calculator once you know how to use it. So when you have to calculate a probability from a normal distribution you can use the functions on your scientific calculator. You can use the normal CDF function from you calculator to compute the area under a normal curve. The function requires lower band and upper band values, the me...

### How To: Find the length of a segment using the midpoint II

First of all in the given question you have to write down the values of the total length of the line segment, PS=15. The length of the line segment, QR =3. Now you have to find the value of line segment RS. Because you know that the Q is the midpoint of the line segments PQ and QS must be equal. Therefore you can find out the length of the half of the segment using the midpoint. Subtract the value of QR from QS. Given that segment PS=15 and Q is the midpoint, you can conclude segment PQ=7.5 a...

### How To: Find a missing angle outside of a triangle

For people who are having problems with certain parts of geometry, this video will offer you advice on how to find a missing angle on the outside of a triangle when you are provided with the measurements of the other two angles in the triangle. Since the sum of the angles in a triangle is always 180 degrees, you should first take the sum of the other two angles and then subtract this from 180 in order to find the measurement of the missing angle in the triangle. Next, since there are also 180...