Answer:
r = 5mm
Step-by-step explanation:
When two shapes are similar, They are the same shape but with 1 or more basic transformations(dilations, reflections, rotations, and translations.). All sides on the new shape (green) are similar to the original shape (blue), meaning they were all dilated by the same scale factor.
First, we need to find our scale factor. To find our scale factor, take 10 and divide it by 4 (These sides are similar and we have established values so we can be sure our scale factor is correct by using these.).
10/4 = 2.5
So, our scale factor is 2.5.
Now, to solve for r, we need to find it's similar side (in this case it's 2 mm.).
Now, simply multiply the original size by our scale factor.
2 * 2.5 = 5.
So, r = 5 mm (Don't forget units, teachers hate that.)
