Question 257378
Draw a large triangle with 2 vertical lines inside the triangle. 
Make one line 5 and the other 35. 
Make the height of the triangle h.
Make the horizontal distance from 5 to vertex, x. 
Make the distance from 5 ft to 35 ft. 75.
Make the distance from 75 ft. to H, 150 ft.
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we need proportions to solve this:
{{{5/x = 35/(75+x)}}}
cross multiply to get
{{{225 + 5x = 35x}}}
solve for x as
{{{225 = 30x}}}
{{{x = 7.5}}}
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Now,
{{{5/7.5 = H/(225 + 7.5)}}}
 cross multiply to get
{{{1162.5 = 7.5H}}}
solving for H, we get
{{{H = 155 ft}}}