Segment BD and AE intersect at C, as shown, AB=BC=CD=CE, and \angle A = 2 \angle B. What is the degree measure of angle D?
Since AB = BC then angle A = C
So
A + B + C = 180
2B + B + 2B =180
5B = 180
B = 36
And angle C = 2 * 36 = 72°
And since CE = CD then angles D and E are equal
D = (180 - 72) / 2 = 108 / 2 = 54°
