∠RAY and ∠YAS are congruent by definition of angle bisector. We will set them equal to each other then and solve for x. 8x-4=5x+20. 3x=24 and x = 8. Now we can find the measure of one of those angles. 5(8)+20=60. Both ∠RAY and ∠YAS are 60°, so 60°+60°=120°. ∠RAS is 120°.