Question

For which acute angle are the sine of the angle and cosine of the angle equal? A. 30º B. 45º C. 60º D. 75º

Answer 1

For this case we have the following definitions:
 $cosx= \frac{C.A}{h}$
 $sinx= \frac{C.O}{h}$
 Where,
 x: angle
 C.O: opposite leg
 C.A: adjacent leg
 h: hypotenuse
 Since the hypotenuse is constant, then the angle for which the legs are equal is 45 degrees.
 We have then:
 $sin45=cos45= \frac{\sqrt{2}}{2}$
 Answer:
 B. 45º

Answer 2

For a right triangle, the sine of an angle is the ratio of the length of the side opposite to it and the hypotenuse and the its cosine is the ratio between the side adjacent to it and the hypotenuse. From the given choices, the angle being referred to is letter B. 45°.