### 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: Divide decimals

Here we are, learning how to divide decimals. So we are dividing a whole number or a fraction by a fraction. How this presenter does this is by moving the decimal two places to the right on both the top and bottom of the sum. In other words, he multiplies the two numbers by 100. So 2 becomes 200 and .25 becomes 25. So much easier to divide 200 by 25 than to divide 2 by .25. Provided you've multiplied both the top and bottom by the same amount, the result will be the same, because the relative...

### How To: Remember "greater than" & "less than" symbols

This video shows you how to easily remember "greater than" and "less than" math symbols. The first thing you have to remember is that "less than" symbol looks like the letter L ("less than" symbol is "<"). When you see this sign, remember that < looks like L and means "less than". The other symbol, "greater than" does not look like the letter L, therefore it cannot be "less than" and it's easier to remember. The "greater than" symbol is ">". That's it! Good Luck!

### How To: Calculate Faster Than a Calculator

When you need to crunch numbers quickly — and I mean really quickly — there's a cool method you can use to multiply two numbers together in just a few seconds.

### How To: Find the volume of a swimming pool

In this video, we learn how to find the volume of a swimming pool. To do this, you will first need to find the measurements of all the sides that are on the pool. After this, you will plug in the measurements that you found into the equation to find the volume. This equation is: V=AH, volume= area(height). So, plug in the area and the height to the equation for A and H and then multiply these two together. Once you do this, you will find the answer! Don't forget to label the units on the fina...

### How To: Factor polynomials in algebra using the GCF method

Need to know how to factor polynomials using the GCF method? Learn how with this free video algebra 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 study for that next big test).

### How To: Change Fahrenheit to Celsius

This video is a tutorial on how to convert Celsius to Fahrenheit. The title of the film says it will teach you how to convert Fahrenheit to Celsius, but it does not. It does just the opposite. The video begins by comparing Fahrenheit and Celsius. He points out that Fahrenheit measures water to freeze at 32 and water to boil at 212. Celsius measures water to freeze at 0 and water to boil at 100. To convert Celsius to Fahrenheit, multiply the Celsius temperature by 1.8 and add 32. Many countrie...

### How To: Find the x & y intercepts of rational functions

In this tutorial the instructor shows how to find the x and y intercepts of rational functions. Finding the intercepts of a rational function is similar to finding the intercepts of other normal equations. You can find the x intercept of the equation by setting the value of y to zero and solving the equation. Similarly you can solve the y intercept by setting the value of x to zero and solving the equation. Now while solving this rational function for intercepts if you face a situation where ...

### How To: Use ">" (greater than) and "<" (less than) symbols

In this video the author explains how to identify the less than (<) and greater than (>) symbols and when to use them. She explains to us to relate the numbers to animals stating that the smaller numbers are smaller animals and bigger numbers are bigger animals. Now she tells us to imagine that smaller animals are eaten up by the larger animals. So she shows a smaller number comes on the left side of '<' sign and bigger number comes on the right side of '<' sign stating that the bigger number...

### News: 3D Sierpinski Tetraeder Made of Straws

Step 1: Make One Tetraeder You need 6 straws of the same length and a cord. Step 2: Add More and More Tetraeder in the Shape of a 3d Sierpinski Tetraeder

### How To: Solve a word problem that asks you to convert yards into miles

Want to know how to express yards as miles? 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 calculate how many yards make up a mile.

### How To: Use a TI-89 to calculate nCr

This video shows you how to do a mathematical representation on computing the nCr function using a TI-89 calculator. You can write the nCr notation in different forms. It can be simplified from nCr to C(n,r). The symbol can either be read "n choose r" or "n taken r at a time" which are from it's probability applications. On the example to find "26 choose 17", go to the Home screen of the TI-89 calculator and then go 2nd 5 which is Math. Go choose probability and then to nCr to type in (26,17)...

### How To: Find the area and volume of prisms

This helpful video gives simple step by step instructions on how to find area and volume of prisms. To find the area of a prism you must first find the area of the base, it may be rectangular, triangular, or otherwise. You must then multiply the area of the base times the height. Examples of all types of scenarios are given to better explain the method of finding the area. To find the volume of a triangular prism you must first find the area of the base. The next step is multiplying the area ...

### How To: Do Celsius to Fahrenheit temperature conversion

The video teaches how to convert degrees Celsius to degrees Fahrenheit. First the boiling points of 32 degrees Fahrenheit and 100 degrees Celsius are plotted on the Y and X axis. Then a line is drawn to join them both. The value m is delta Y (boiling point minus freezing point, i.e., 212-32)/ delta X (boiling point minus freezing point, i.e., 100-0). So m works out to 180/100 or 1.8. Then the formula y=mx+b (intercept of y = 32) is used, substituting X with Celsius and y with Fahrenheit, to c...

### How To: Find the area of an oblique triangle using formulas

In this tutorial the instructor shows how to find the area of an oblique triangle using different formulas. To find the area of an oblique triangle there are different formulae. The first formula to calculate the area of a triangle is area A = (1/2) * a * b * Sin(C), where a and b are the lengths of the two sides of the triangle and C is the value of the angle of the triangle that lies in between the two sides a, b. Now substitute these values in the given formula to find the area if you have...

### How To: Divide fractions using the inverse

Learn to divide fractions using the inverse with this video. It is an easy way to divide the fractions just by multiplying the two fractions but reversing one of them. For example consider two fractions to be divided, (1/4) and (3/5). Then write the two fractions beside, one in the same way and another in the reverse order like remain (1/4) as it is and reverse (3/5) as (5/3). Then multiply these two terms (1/4) * (5/3) then the solution will be (5/12).

### How To: Subtract fractions and mixed numbers

See how to subtract fractions. Turn those mixed numbers into improper fractions to solve. Improve your math skills!

### How To: Prove a triangle inscribed in a circle is right angled

When a triangle is inserted in a circle in such a way that one of the side of the triangle is diameter of the circle then the triangle is right triangle. To prove this first draw the figure of a circle. Now draw a diameter to it. It can be any line passing through the center of the circle and touching the sides of it. Now making this as the side of a triangle draw two lines from the ends of the diameter to a point on the circle. Now join the center of the circle to the other vertex of the cir...

### How To: Divide variables

This is a helpful video provided by Math Problem Generator. It deals with the complex challenges of dividing variables. The audio is great and provides specific examples of dealing with multiple types of this problem. The video lays out three simple steps. The first being to simplify the coefficient, the second being to divide the variable, and the third being to deal with the results of the division. The information is clearly presented and best of all it's free. I think we all wish there we...

### How To: Determine if you have a function

In this tutorial, we learn how to determine if you have a function. You will start off with two functions and their points. The 'x' values make up the domain of the function and the 'y' values make up the range. The input values are the domain and the output are the range. If you're checking to see if you have a function, you will need one 'y' for every 'x'. This means that each value has another one that goes with it. Each of the points need to have one partner with them, no more and no less...

### How To: Subtract a mixed number from a proper fraction in basic math

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 free math tutorial, you'll learn how to subtract a mixed number from a fraction in basic arithmetic.

### 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: 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 Leg Lengths and Hypotenuse of a 45 45 90 Triangle

A 45 45 90 triangle is a special right triangle because you can use short cuts to find leg length and hypotenuse length. This video solves two problems involving leg length and hypotenuse length.

### 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: Determine if lines are parallel or perpendicular

In this tutorial, we learn how to determine if lines are parallel or perpendicular. You will be given two straight line equations. First, remember that parallel lines have equal slope, identical to each other. Perpendicular lines have negative reciprocal slopes. For example, 2/3 and -3/2 would be a perpendicular line. If you think of parallel lines, then you can graph them to see what they look like when written down. Then, graph the other lines to see what they look like as well. Once you un...

### 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: Subtract fractions with unlike denominators

In order to subtract mixed fractions, you'll need to look at the denominators carefully. If the denominators do not match, you'll need to find a common denominator. For example, 5 2/3 minus 3 4/5 do not have the same denominator. The lowest common denominator for them is 15.

### How To: Solve basic linear function word problems in algebra

Need some help solving linear function word problems? See how it's done with this free video math lesson. Need help finding the 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 o...

### How To: Find and sketch the domain of a multivariable function

Looking for a primer on how to find and sketch the domain of a function z = f(x, y) in calculus? Learn how with this free video calc 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: Use a protractor to make a pie chart

If you have a circular or semicircular protractor like the one used in this video, making a pie chart is as easy as – well — pie. This will teach you how to use your protractor to measure out each individual slice in your pie chart. Learn how to visualize statistical data through hand-drawn pie charts with this free video math lesson.

### How To: Use and find x & y-intercepts in algebra

A straight line can be represented in the form of a liner equation containing two variables x and y. When the equation is graphed on a pair of coordinate axes, the line passes cut through the axes in two points. The point where the line cuts the x-axes is called as its x coordinate and the point where the line cuts the y-axes is called as its y coordinate. In this way a line has x-intercept and y-intercept. The x-intercept of a line lies on x axes and is in the form (a,0). Similarly the y-int...

### How To: Find the area of a circle with a given radius

This video describes how to find the area of a circle given a radius of 4cm. The video begins by describing the formulas needed to find the area of the circle. The narrator cautions the viewer on a few common mistakes that people frequently make while using these formulas, such as not properly squaring the radius of the circle. The solution to the formula for a 4cm radius is 50.24 cm^2. The video then demonstrates that this value makes sense by overlaying a grid onto the circle and visually s...

### How To: Find the equation of a line given 2 points

This tutorial teaches you how to find a mathematical equation of a line given 2 points that exists on the line. The tutorial starts off with 2 points labeled (2,-4) and (3,6). The first step is to determine the slope of the line using the formula given in the tutorial in blue. The slope is then solved as 'm'. Plug the slope and the points into another formula given in green. The tutorial maker provides a tip that one can use x1 and y1 or x2 and y2, however, it must be consistent. After, solve...

### How To: Calculate percentages in your head

This video explains how to calculate percentages in your head. To calculate a percentage in your head, start by breaking the percentage off into smaller units. For example 25% is 10 + 10 + 5. 30% is 10, 10, and 10. Now you have numbers you can easily work with in your head. Find 10% of the number. This is easily done by one of two methods. You can either move the decimal point one place to the left or you can drop the last number. Dropping the last number sometimes gives you an estimate, thou...

### How To: Find the percentage of a number

In this tutorial the author explains of how to compute percentages of a given number. He explains that x percent of some number y is x multiplied by y and divided by 100. He says that of means multiply and percentage means for hundred. He goes on and explains this concept with numerous examples. He suggests a small trick to move the decimal point of a number two digits to the left to get it divided by hundred. The author demonstrates many more similar tricks and short cuts using which one can...

### 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: Multiply Any Number by 11 with a Super Fast Mental Trick

Most of the time, when I’m bored during math class, I play with my calculator to satisfy my boredom. Recently, I've discovered that when multiplying any number by 11, 111, or any number similar to it, that it has a pattern (though I guess everything in math has a pattern). I don't know if this technique is original, because I didn't read anything about this. It's just mere observation. If it’s a tried and true technique, let me know.

### 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...