Question

a pole 7 feet tall is used to support a guy wire for a tower, which runs from the tower to a metal stake in the ground. after placing the pole, rashaad measures the distance from the pole to the stake and from the pole to the tower, as shown in the diagram below. find the length of the guy wire, to the nearest foot. (diagram is not to scale.)

Explanation:

Step1: Use similar triangles property

Let the height of the tower be \(h\). Since the two triangles (formed by the pole and the tower with the ground) are similar. The ratio of their corresponding sides is equal. So, \(\frac{h}{18 + 4}=\frac{7}{4}\).

$$h=\frac{7\times(18 + 4)}{4}=\frac{7\times22}{4}=\frac{154}{4}=38.5$$

Step2: Use Pythagorean theorem

The length of the guy - wire \(l\) (hypotenuse of the right - triangle with base \(18 + 4=22\) and height \(h = 38.5\)) is found using \(l=\sqrt{(18 + 4)^{2}+h^{2}}\). Substitute \(h = 38.5\) and base \(b=22\).

$$l=\sqrt{22^{2}+38.5^{2}}=\sqrt{484+1482.25}=\sqrt{1966.25}\approx44.34$$

Answer:

\(44\) feet