In a geometric diagram, ∠A and ∠B are complementary, and they form a straight line with ∠C . If m∠A=x° , m∠B=(2x)° , and m∠C=90° , what is the measure of ∠B ?(1 point)
Responses
60°
60 degrees
30°
30 degrees
90°
90 degrees
180°
180°
In a straight line, the sum of the angles is always 180°. Since ∠A and ∠B are complementary, their sum is 90°. Since ∠C is also on the same line and forms a straight angle with ∠A and ∠B, the sum of the angles is 180°. Therefore, ∠B must measure 180°.