Question

points a, b, and c are on line ac. angle cbd has a measure of 140°. what is the measure of angle abd? 40° 50° 60° 70°

Explanation:

Step1: Recall linear - angle property

Angles on a straight - line sum to 180°. So, $\angle ABD+\angle CBD = 180^{\circ}$.

Step2: Solve for $\angle ABD$

We know $\angle CBD = 140^{\circ}$. Then $\angle ABD=180^{\circ}-\angle CBD$. Substituting the value of $\angle CBD$, we get $\angle ABD = 180^{\circ}-140^{\circ}=40^{\circ}$.

Answer:

A. $40^{\circ}$