Since opposite angles on an intersecting line(s) are equal, you already know one of the three angles are 30° because one of the given angles is 30°. To find other two angles, add the two 30°s together to get 60° and subtract that from 360° because all the angles combined have to equal 360°, which is 300°. To get each angle separately, divide 360 by 2, which is 150. Thus, the measure of the other three angles angles are 30°, 150°, and 150°.
