The given formula is
s = rwt
From the information given,
s = pi/5 * m = mpi/5
r = 5m
t = 5
By substituting these values into the formula, we have
mpi/5 = 5m * w x 4
mpi/5 = 20mw
m cancels out on both sides of the equation. It becomes
pi/5 = 20w
Recall, pi is a constant whose value is 3.14
Thus,
3.14/5 = 20w
0.628 = 20w
Dividing both sides of the equation by 20, we have
20w/20 = 0.628/20
w = 0.0314