Question

3. Find m D
(2x+14)
(x + 7)
E
B
60
23
53
30

Answer 1

Explanation:

∠ABC + ∠CBD = 90 so filling in the expressions for these angles:

(2x + 14) + (x + 7) = 90 and

3x + 21 = 90 and

3x = 69 so

x = 23. To find the measure of angle ABC in particular, we sub in a 23 for x:

x + 7 --> 23 + 7 = 30°, the last choice there.