Question

A triangle with vertices at A (0, 0) B (0, 4) and C( 5, 9) is dlated to yeld a triangle with vertices at A(0, 0) , B(0, 10) and C (15, 0) The origins the center of dilation. What is the scale factor of the dilation?

A 1.5
B 2
C 2.5
D 3

Answer 1

The basic formula to find the scale factor of a dilated figure is: Scale factor = Dimension of the new shape ÷ Dimension of the original shape.

So to find the scale factor:

You take any point listed and pick x or y value, we will be using C. For this point we must use x because y = 0 (side note: if any value = 0 you can not use it if the center of dialtion is on any point on the triangle). The original value of x was 5 and the new one is 15 so new/old. For this example it would be 15/5 which = 3. this number is the scale factor so the answer is D