What is the measure (in degrees) of the smallest interior angle of a triangle in which the exterior angle measures have the ratio 3:4:5?
The sum of the exterior angles = 360°
And the largest exterior angle will be supplemental to the smallest interior angle
And the largest exterior angle = (5 / [ 3 + 4 + 5b] ) * 360 = (5/12) (360) = 5 * (360/12) = 5 * 30 = 150°
So....the smallest interior angle = 180 - 150 = 30°