Find the radian measure of the central angle of a circle of radius 5 yards that intercepts an arc of length 15 yards.
The radian measure of the central angle is
(Type an integer or a fraction. Simplify your answer.)

White shapes and black shapes are used in a game. some of the shapes are circles. while the rest are squares. the ratio of the number of white shapes to the number of black shapes is 5: 11. the ratio of the number of white cicrles to the number of white squares is 3: 7. the ratio of the number of black circles to the number of black squres is 3: 8. work out what fraction of all the shapes are circles.