McGraw Hill Integrated II, 2012
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McGraw Hill Integrated II, 2012 View details
5. Angles of Elevation and Depression
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Exercise 38 Page 669

Recall that in a 45^(∘)-45^(∘)-90^(∘) triangle the legs are congruent.

23 ft

Practice makes perfect

We are given that Imani needs to determine the height of a tree. She holds a 45^(∘) triangle so that one leg is horizontal and she sights the top of a tree along the hypotenuse. We also know that she stands 6 yards from the tree and her eyes are 5 feet from the ground.

First, let's convert yards to feet. Recall that there are 3 feet in each yard.

6yd=6*3ft=18ft Let's add this information to our diagram. Notice that a 45^(∘) triangle is a right isosceles triangle. Therefore, the legs of this triangle are congruent.

As we can see, the height of the tree is the sum of 18 and 5. 18+5=23 The height of the tree is 23 feet.