Question

If AC = 20, AE = 25, and AB = 5, what is the length of AD?

Answer 1

You'll have the formula using the variable designation from the illustration as:
(AC)(AB)=(AE)(AD)
Substitute the values and you'll be able to find AD..

Answer 2

i have no idea

Answer 3

is the answer 4?

Answer 4

yep.
(AC)(AB)=(AE)(AD)
(20)(5) = (25)(AD)
\[AD = \frac{ 20(5) }{ 25 }\]
\[AD = 4\]