In this video the author shows how to do similarity transformations. He says that similarity transformations are used to draw the similar images at a different location and the k value is most important while doing this kind of transformation. He says that a negative k value tells that the copy of the shape will end at the opposite side of the origin to the original shape. He says that a positive k value tells that the copy will lie on the same side of the origin. Next thing about the k value is that the magnitude of it tells the size of the copy to be drawn. He tells that a k value of 2 means that we need to draw a new shape which is now double the size of the original shape. Now he calculates the distance of the vertex of the shape from the origin and multiplies it with the k value and depending on the sign of the k value draws lines through the origin from the vertex of the original shape. Now after joining the end points of these lines the similarity transformation of the original shape is obtained. This video shows how to perform similarity transformations based on the k size.