McGraw Hill Glencoe Geometry, 2012
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McGraw Hill Glencoe Geometry, 2012 View details
5. Angles of Elevation and Depression
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Exercise 8 Page 583

We are given that Miko and Tyler are visiting the Great Pyramid in Egypt. We know that they are standing feet apart and that they are both feet tall. Let represent the horizontal distance from Tyler to the pyramid.

We are also given that their angles of elevation to the top of the pyramid are and respectively.

We are asked to evaluate how tall the pyramid is. To do this, notice that this height is the sum of the boys' height and the height of the pyramid above their line of sight. Let represents the height above the boys line of sight.

To evaluate the lengths of the missing sides, we can use one of the trigonometric ratios. Let's recall that the tangent of is the ratio of the leg opposite to the leg adjacent Using this definition, we can create the equations for and
As we can see, we need to solve the system of equations. To do this, we can use the Substitution Method. Our first step will be to isolate in the first equation.
Next we will substitute the value of into the second equation.
Solve for
The value of is approximately feet. By substituting this value into the first equation, we can find the value of
The value of is approximately feet.
Finally, we can evaluate the total height of the pyramid.
The height of the pyramid is approximately feet.