Trig Question help! If an object moves along a circle of radius...

...r units, then its linear velocity, v, is given by v=r(theta/t), where (theta/t) represents the angular velocity in radians per unit of time. Find the angular velocity for each:

a.) a pulley of radius 8cm turns at 5 revolutions per second, ans: 150.8 cm/s
b.) a bike tire of diameter 26 inches 3 revolutions per second. ans: 245.04 in/s

Please show me your solutions. Thanks in advance

a) theta/t=5 rev/s(2π rad/1 rev)
=10π rad/s

b) theta/t=3 rev/s (2π rad/1 rev)
=6π rad/s