Question

in the figure, ∠k≅∠r. select the vertices of all angles in the figure for which the cosine is equal to sin(l).

Explanation:

Step1: Recall co - function identity

We know that $\sin\theta=\cos(90^{\circ}-\theta)$ for any acute angle $\theta$. In right - triangle $JKL$, $\angle J = 90^{\circ}$, so $\angle K+\angle L=90^{\circ}$, then $\sin(L)=\cos(K)$. In right - triangle $QRS$, $\angle Q = 90^{\circ}$, and since $\angle K\cong\angle R$, then $\sin(L)=\cos(R)$ as well.

Answer:

K, R