Thread: Height of Flagpole
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Old January 6th, 2009, 09:22 AM
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Originally Posted by magentarita View Post
From a point 100 feet away in front of a public library, the angles of elevation to the base of the flagpole and the top of the flagpole are 28 degrees and 39 degress 45', respectively. The flagpole is mounted on the front of the building's roof. Find height of the flagpole.

Must I change 39 degrees 45' into a degree first?

How is this done?
1. 45' = \left(\dfrac{45}{60}\right)^\circ = 0.75^\circ

2. You are dealing with 2 right triangles. Use tan-function to calculate the second leg:

The length of the flagpole is:

f = 100\cdot \tan(39.75^\circ) - 100\cdot \tan(28^\circ) = 100 \cdot (\tan(39.75^\circ) - \tan(28^\circ)) = 29.998...\approx 30'
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