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 16 Page 667

First, find the value of x using the definition of tangent.

≈ 20.9 ft

Practice makes perfect

Let's begin with redrawing the given picture. We will name the consecutive letters.

Since we are asked to evaluate the length of AC, we need to find the value of x. To do this, we can use one of the trigonometric ratios. Let's recall that the tangent of ∠ A is the ratio of the leg opposite ∠ A to the leg adjacent ∠ A. Using this definition, we can create an equation for tan 70^(∘). tan 70^(∘)=30/x Let's solve the above equation.
tan 70^(∘)=30/x
xtan70^(∘)=30
x=30/tan 70^(∘)
x=10.9191...
x≈ 10.9
The value of x is approximately 10.9 feet. Therefore, to find the distance between the worker standing on the ground and the truck, we will add this value and 10. AC= 10+10.9=20.9 The worker on the ground is standing approximately 20.9 feet from the truck.