Two arcs have the same length. One arc is intercepted by an angle of 3π / 2 radians in a circle of radius 15 cm . If the radius of the other circle is 25 cm , what central angle intercepts the arc?
a. 3π/2 radians b. 9π/10 radians c. 5π/2 radians d. 5π / 3 radians