Let abc be a triangle and d be a point on ac such that ab = bd = cd. given that angle bac is 70 degrees, find angle abc
b
x x
a d x c
angle bac = 70
ab =bd ....so.....
angle adb = 70
So angle abd = 180 - 2(70) = 40
And angle bdc = 180 - 70 = 110
bd = dc
So angle dbc = (180 -110) / 2 = 35
So....angle abc = angle abd + angle dbc = 40 + 35 = 75°
