To get the congruent angles we shall use the sine rule since we have the length of at least 1 side and the values of the angles.
Base length=12 inches
Base angles=50°
Third angle=180-(100)=80°
thus applying the sine rule we shall have:
a/sin A=b/sin B=c/sin C
thus we can get the congruent side as follows:
a/sin 50= 12/sin 80
a=(12 sin 50)/sin 80
a=9.334 inches
since the sides are congruent then the other congruent side will have a length of 9.334 inches
