OVER DUE ASSIGNMENT! click picture!!

Sam claims that cos x =sin y if x and y are congruent angels. is sam correct ?

Can someone tell me if this is perpendicular? !

Sanderson is having trouble with his assignment. his shown work is as follows: − 3 7 7 3 = − 3 7 × 7 3 = − 21 21 = −1 however, his answer does not match the answer that his teacher gives him. complete the description of sanderson's mistake. find the correct answer.