Question

Robert is lying on the ground, looking at the top of a flagpole. The angle of elevation to the top of the flagpole is
55° . What is the height of the flagpole if the distance from his eyes at the ground to the base of the flagpole is
400 ft? Round to the nearest foot.
550
400 ft​

Answer 1

Answer:

Height of flagpole = 571 ft

Step-by-step explanation:

Given:

Angle of elevation to the top of the flagpole is 55° .

Distance from the eyes to the base of flagpole = 400 ft.

To find the height of the flagpole.

Solution:

We can draw the situation as a right triangle as shown below.

In triangle ABC.

$BC=400\ ft$

∠C= 55°

To find the length AB (height of the flagpole).

Applying trigonometric ratio :

$\tan\theta=\frac{Opposite\ side}{Adjacent\ side}$

$\tan C=\frac{AB}{BC}$

Plugging in values.

$\tan 55\°=\frac{AB}{400}$

Multiplying both sides by 400.

$400\tan 55\°=\frac{AB}{400}\times 400$

$571.26=AB$

∴ $AB\approx 571\ ft$

Height of flagpole = 571 ft