Question 1141232: a regular pentagon ABCDE is inscribe in a circle, centre O. calculate angle ABD. well explain with the diagram
Answer by greenestamps(13200)   (Show Source):
You can put this solution on YOUR website!
Angle B, an interior angle of a regular pentagon, is 108 degrees.
Angles ABE and CBD, being base angles in isosceles triangles with vertex angles of 108 degrees, are each 36 degrees.
That makes angle EBD 36 degrees.
Then angle ABD is angle ABE plus angle EBD, which is 36+36 = 72 degrees.
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