Exercise 28 Page 520

Angles formed above and below a horizontal line have specific names. The angle formed above a horizontal line is called an angle of elevation. The angle formed below a horizontal line is called an angle of depression.

Notice that these two angles are congruent because they are alternate interior angles. Therefore, their measures are equal. (x+14)= 5(x-2) Let's solve our equation for x!

(x+14)=5(x-2)

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Solve for x

RemovePar

Remove parentheses

x+14=5(x-2)

Distr

Distribute 5

x+14=5x-10

SubEqn

LHS-5x=RHS-5x

- 4x+14=- 10

SubEqn

LHS-14=RHS-14

- 4x=- 24

DivEqn

.LHS /(- 4).=.RHS /(- 4).

x=6

Now that we found x, we will substitute its value into the given expressions to find the measure of each angle.

	Expression	Substitute	Value
Angle of Elevation e	5(x-2)^(∘)	5( 6-2)^(∘)	20^(∘)
Angle of Depression d	(x+14)^(∘)	( 6+14)^(∘)	20^(∘)