A tall standpipe with an open top (see figure) has diameter d = 2.2 m and wall

Question:

A tall standpipe with an open top (see figure) has diameter d = 2.2 m and wall thickness t = 20 mm.
(a) What height h of water will produce a circumferential stress of 12 MPa in the wall of the standpipe?
(b) What is the axial stress in the wall of the tank due to the water pressure?