MathDB

1

Part of 1997 Canadian Open Math Challenge

Problems(1)

COMC 1997 #1

Source:

6/8/2017
In triangle ABC, ∠\angle A equals 120 degrees. A point D is inside the triangle such that ∠\angleDBC = 2 ×∠\times \angle ABD and ∠\angleDCB = 2 ×∠\times \angleACD. Determine the measure, in degrees, of ∠\angle BDC. [asy]
pair A = (5,4); pair B = (0,0); pair C = (10,0); pair D = (5,2.5) ; draw(A--B); draw(B--C); draw(C--A); draw (B--D--C); label ("A", A, dir(45)); label ("B", B, dir(45)); label ("C", C, dir(45)); label ("D", D, dir(45));
[/asy]