Question

If the measure of ∠ABD is 112°, determine the value of x.

ABC = (3x + 7)
CBD = (2x + 5)

Answer 1

Since ∠ABD is an exterior angle of triangle ABC, it is equal to the sum of the two opposite interior angles, ∠ABC and ∠CBD.

So,
112 = (3x + 7) + (2x + 5)
112 = 3x + 7 + 2x + 5
112 = 5x + 12
5x = 100
x = 20

Therefore, the value of x is 20.