A rectangle is 18 cm long with a diagnal of 22.2cm How wide is the rectangle?

A2 + B2 = C2

182+ B2= 22.22

324 + B2 = 492.84

324 + B2 - 324 = 492.84 - 324

B2 = 168.84

B = square root of (168.84)

B = 12.993844696624629121071720652075... cm