Segment BD and AE intersect at C, as shown, AB=BC=CD=CE, and angle A = 3 angle B. What is the degree measure of angle D?
Since AB = BC, then angles A and C are equal
So
A + B + C =180
3B + B + 3B =180
7B = 180
B = 180 / 7
C = 3 (180/7) = 540/7 degrees
And since CD = CE , then angles D and E are equal
So
C + D + E =180
(540/7) + D + D = 180
2D = 180 - 540/7
2D = 720 / 7
D = 720 / 14 degrees ≈ 51.43°