This information implies that we do not have a right triangle, to solve the question we proceed as follows:
Angle of the base of the pole would be 81°
Find the top angle made by the sun and the top of the pole
180-81-64=45°
let the the length of the pole be a, then angle A=64°
Using sine law
a/sin A=b/sin B
thus
a/sin 64=21/sin 45
a=21*sin 64/sin45
a~26.69 ft
Th length of the pole is 26.69 ft