We are going to use SAS. We need to find values of CR.
ΔCRK is right triangle, so from Pythagorean theorem
|CR|² +|RK|²=|CK|²
|CR|² + 4²= 5²
|CR| = 3
Corresponding sides should be in proportion:
OY/CR=YU/RK
16/4= 12/3
4/1 =4/1
These corresponding sides are in proportion, also we have m∠U=m∠R=90⁰.
So, we have 2 corresponding sides are in proportion and angles between them are congruent, so by SAS these triangles are similar. Because of it their corresponding angles are congruent:
m∠O=m∠C, m∠Y=m∠R, m∠U=m∠K.