I'm stuck on this homework question. I forgot the formula to find the side. This is 9th grade geometry.

x = 2root(22)

see image.

Step-by-step explanation:

The triangle shown is one big triangle cut into two more smaller triangles: one medium-sized and one smaller.

ALL THREE TRIANGLES ARE SIMILAR BY AA.

Set the two smaller triangles up so you can see the corresponding sides. x is the short leg in one triangle and it is the long leg in the smallest triangle. Set up a proportion.

22/x = x/4

crossmultiply

x^2 = 22•4

x^2 = 88

square root both sides.

x = sqroot(88)

x = 2sqroot(22)

see image.