Answer:
C.) 80 ft
Explanation:
Using the diagram, the little lines that intersect the sides of the triangle tell us that those lengths are equal. When you see a single line, any other side length that has a single line is the same value.
We'll call our unknown side length, the height of the tree, a, while the height of the building will be A. And we'll label the other two given side lengths b and c.
We know that:
So the entire base, C, must be 2(144) and the entire hypotenuse, B, must be 2(120).
Basically, the values of the triangle are doubled. So using this information, we can determine that the height of the tree, a, must be 160/2. Which is 80.
(This is a little confusing, sorry!)
You can check your work by making a proportion:
288/2 = 144/1
240/2 = 120/1
so:
160/2 = x/1
Solve the proportion by solving for x.
Cross multiply, then solve for x and you'll find that x = 80.