Point $D$ is on side $AC$ of triangle $ABC$, $\angle ABD=15^{\circ}$ and $\angle DBC=50^{\circ}$. What is the measure of angle $BAD$, in degrees?
Note that angle BDC = 90 - 50 = 40°
And angle ADB is supplemental to this = 180 - 40 = 140°
So
BAD + 15 + 140 = 180
BAD + 155 = 180
BAD = 180 - 155 = 25°
Angle BAD = 180° - ( 15° + 50° +90° )
+383 
