Answer:
The correct answer is second option
78°
Explanation:
Points to remember
The measure of arc BC = 2 * measure of angle BDC
To find the measure of arc BC
From the figure we can see the BD is the diameter of the given circle.
Therefore the ΔBDC is right angled triangle. m<C = 90°
m<CBD = 51° (given)
m<CBD + m<BDC = 90
m<BDC = 90 - m<CBD
= 90 - 51 = 39
Therefore measure of arc BC = 2 *m<BDC
= 2 * 39
= 78°
The correct answer is second option
78°