Answer: 30 feet
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Work Shown:
x = height of tree in feet
The larger triangle, and the smaller triangle that fits inside the larger, are similr triangles.
So we can form the proportion
x/5 = 48/8
Note how x/5 is the result of dividing the larger vertical side (x) over the smaller vertical side (5)
The same applies with 48/8. The larger triangle's horizontal side is 8+40 = 48. The corresponding horizontal side for the smaller triangle is 8
Cross multiply to solve for x
x/5 = 48/8
8*x = 5*48
8*x = 240
8*x/8 = 240/8
x = 30
The tree is 30 feet tall