Question

What is the value of x? sin64°=cosx Enter your answer in the box. x = ? degrees

Answer 1

Sin and cosine of the acute angle are complementary trigonometric functions. This means that between these trigonometric functions, the rule of complementary acute angles applies: sin64° = cos(90°-64°) = cos26°

So, if we have given cos64° = cosx  and we want to determine the value of the acute angle x, given the complementarity of the angles to 90 degrees, the required value of the angle x is 26°.

The answer is: x = 26°

Answer 2

Sin(64)=0.899=cosx
cos-1(0.899)=x
x=25.973°