Question

1. if ac is the angle bisector of ∠dab, and m∠dac = 42°, what is m∠dab? a) 21° b) 42° c) 84° d) 100°

Explanation:

Step1: Recall angle - bisector property

An angle bisector divides an angle into two equal parts. So $\angle DAB = 2\angle DAC$.

Step2: Substitute the given value

Given $\angle DAC = 42^{\circ}$, then $\angle DAB=2\times42^{\circ}$.
$\angle DAB = 84^{\circ}$

Answer:

C. 84°