Question

In triangle ABC, ZA and B are complementary, where cos A = 0.5.

Answer 1

Answer: Angle B measures 30 degrees.

Step-by-step explanation: First of all, angles A and B are complimentary, which means they both add up to 90. Also the cosine of angle A has been given as 0.5

The value in degrees, of an angle whose cosine is 0.5000 is equal to 60 degrees (this can be verified with a table of values, or by checking the second function Cosine of a calculator).

Where angle A has been determined to be 60 degrees and angles A and B are complimentary, angle B is derived as follows;

Angle A + Angle B = 90 {Complimentary angles equal 90}

60 + Angle B = 90

Subtract 60 from both sides of the equation

Angle B = 30 degrees