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: Recognize linear pair

Angles \( \angle ABD \) and \( \angle CBD \) form a linear pair, so their sum is \( 180^\circ \).
\( \angle ABD + \angle CBD = 180^\circ \)

Step2: Substitute known angle

Given \( \angle CBD = 140^\circ \), solve for \( \angle ABD \).
\( \angle ABD = 180^\circ - 140^\circ \)
\( \angle ABD = 40^\circ \)

Answer:

\( 40^\circ \) (corresponding to the option "40°")