What Transformations were applied to ABCD to obtain A'B'C'D

The fence around a quadrilateral-shaped pasture is 3a^2+15a+9 long. three sides of the fence have the following lengths: 5a, 10a-2, a^2-7. what is the length of the fourth side of the fence?

Given the two similar triangles, how do i find the missing length? if a=4, b=5, and b'=7.5 find a'

Gabrielle's age is two times mikhail's age. the sum of their ages is 84. what is mikhail's age?