Answer:
78 degrees
Step-by-step explanation:
Mainly because the measure of the arcs intercepted by the interior angles equals 2 times those interior angles.
so arc DC = 2 * angle DBC = 2 * 51 degrees = 102 degrees.
We also see that because BD is a diameter the angle BCD that intercepts it is 90 degrees because half-circle arc BD = 2 * angle BCD
180 degrees = 2 * angle BCD
also we want arc BC.
we know that the total circle is the sum of all 3 arcs.
arc BC + (half-circle) arc BD + arc DC = 360 degrees
arc BC + 180 + 102 = 360 degrees.
arc BC = 360 - 180 - 102 = 78 degrees
Answer:
The answer is D 129
Step-by-step explanation:
Depends on the question, we can see that angle BCD is a inscribed angle. It reach the point BD. Because the line BD is a diameter. So the angle BCD covered half of the circle which is 180 degree.
Then we use 360-180-51=129 degree.
