Question

DA is a diameter of circle C. What is the measure of arc BD?

Answer 1

130°

Explanation:

1. to connect point A and B (green line);

2. the 1st row: to define measure of the angle ABD (90°);

3. the 2d row: to define measure of the angle BAD in the ΔABD (65°);

3. the 3d row: to calculate measure of the arc BD using the formula m(arc BD)=2*m(∠BAD).