Given the right triangle below, if AB = 4 and BC = 4, find AC.
A
B
C

The length of AC is found using the Pythagorean theorem which is a^2+b^2=c^2.

In this case your equation would look like 4^2+4^2=c^2.
Four to the power of two is 16 so 16+16=c^2.
16+16=32
32=c^2
Root 32 = c

Length AC is root 32.