Desperate for help
Timed Test

If two sides of a triangle are congruent, then the angles opposite those sides are congruent. the converse of the base angles theorem, states that if two angles of a triangle are congruent, then sides opposite those angles are congruent.

Translate to english do we can provide answers

Use pythagorean’s theorem and find the missing side lengths of the two smaller triangles and add them together
13^2 - 12^2 = 5
15^2 - 12^2 = 9
5+9 = 14
14 is the length of each side of the square
14^2 + 14^2 = 19.8
19.8 is the diagonal length of the inside if the square