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 90° 90 degrees 30° 30 degrees 60° 60 degrees 180° 180 degrees
Since ∠A and ∠B are complementary and form a straight line with ∠C, we can set up the equation:
∠A + ∠B = 180°
Substituting the given values:
x° + (2x)° = 180°
Combining like terms:
3x° = 180°
Dividing both sides by 3:
x° = 60°
Therefore, the measure of ∠B is 2x° = 2(60°) = 120°.
The correct answer is 120 degrees.