The kinetic energy the monkey has at the bottom of the swing is 1/2 x m x v2 = 1/2 x 16.9 kg x 11.32 m2/s2 = 1029 joules.
Neglecting air resistance etc., the KE is converted to potential energy at the top of the swing. PE =mgh where m is mass, 9.8 m/s2 and h the height above the bottom of the swing. Also, PE = KE.
PE = KE =16.9kg x 9.8 m/s2 x h. Solve for h.
h = 1029 j / (16.9 kg x 9.8 m/s2) = 6.21 m above the bottom- most point.