This problem is done in a triange like graph with c located at the top of the tower and a being right at the foot of the tower with b coming out to the right and where between a & b is the 171 feet that's the best I can describe it

Closed to tourists since 1990 the leaning tower of pisa in Italy leans at an angel of aboout 84.7 it is 171 feet from the base of the tower the angle of the evecation to the top is 50 find the distance to the nearest tenth of a foot from the base to the top of the tower.

There are different approaches, but you could use the law of sines to find AC and then use that to find the height of the tower. Assuming I am interpreting your explanation correctly:

\frac{sin(45.3)}{171}=\frac{sin(50)}{AC}

Once you have AC, use cosine to find the tower height.