Geometry Problem 1429: Triangle, Median, 15-30 degree, Angle, Congruence

Problem

In a triangle ABC, BD is a median. If angle ABD = 15 degree and angle DBC = 30 degree, find the measure of the angle A.
This entry contributed by Sumith Peiris, Moratuwa, Sri Lanka. Trigonometry is not allowed.


 

 
 
 

See also:
Poster of problem 1389.