Question

Under a dilation, triangle XYZ where X(1, 3), Y(-2, -4), and Z(5, -2.5) becomes triangle X’Y’Z’ where X’(2.5, 7.5), Y’(-5, -10), and Z’(12.5, -6.25). What is the scale factor for this dilation?

A) 2/5
B) -2/5
C) 2.5
D) -2.5

Answer 1

https://www.desmos.com/calculator/3qt1junkeu

Here's a graph of it. The red is the original(XYZ) and the blue is the new(X'Y'Z').

Answer 2

Does it get bigger or smaller?

Answer 3

Actually, we can just divide the points.

Let's take Point X and point X' and divide.

Point X: (1, 3)
Point X': (2.5, 7.5)

2.5 / 1 = ?
7.5 / 3 = ?

Answer 4

Can you do that? @Addicto_

Answer 5

2.5/1 = 2.5
7.5/3 = 2.5

Answer 6

Yes, so 2.5 is the scale factor.

Answer 7

ok thank you :)