In a geometric diagram, A and B are complementary, and they form a straight line C. If m A = x, m B = (2x), and m C = 90, what is the measure of B?
A. 90
B. 60
C. 180
D. 30
Since A and B are complementary angles, their measures add up to 90 degrees.
We are given that m A = x and m B = 2x.
Therefore, the equation x + 2x = 90 holds.
This simplifies to 3x = 90.
Dividing both sides of the equation by 3, we find that x = 30.
Since the measure of B is given as 2x, we can substitute x = 30 into this expression to find the measure of B:
m B = 2(30) = 60
So, the measure of angle B is 60 degrees.
Therefore, the correct answer is option B. 60.