Question

1. calculate for m∠aob if m∠aoc = 110° and m∠boc = 20°. 30° 70° 90° 130°

Explanation:

Step1: Identify angle - relationship

We know that $\angle AOC=\angle AOB+\angle BOC$.

Step2: Solve for $\angle AOB$

By re - arranging the formula, we get $\angle AOB=\angle AOC - \angle BOC$.
Substitute $\angle AOC = 110^{\circ}$ and $\angle BOC = 20^{\circ}$ into the formula: $\angle AOB=110^{\circ}-20^{\circ}=90^{\circ}$.

Answer:

C. $90^{\circ}$