Question 87256
Let angle A = 50
Let Angle B = 84.7
Since the angles of a triangle must add up to 180, then 
Angle C = 180-50-84.7 = 45.3
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Now, use the law of sines to find the distance from the base to the top of the tower. That is the side of the triangle opposite Angle A. The distance of 170 feet is the side opposite Angle C. So:
{{{a/sin(A)=c/sin(C)}}}
{{{a/sin(50)=170/sin(45.3)}}}
Now, just solve for a.
Good Luck,
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