The pilot of a glider plane wants to estimate his altitude. He picks a landmark ahead and measures the angle of depression to be 20 degrees. He flies another 800 feet towards the landmark, remaining at the same altitude. The angle of depression from his new location to the same landmark is now 21.4 degrees. What is the glider's altitude?

Explanation:

The figure attached shows sketches the situation described.

You have two right triangles.

For the right triangle with the plane on the position A, you can write:

         ⇒ H = (800 + x) tan(20º)

For the right triangle with the plane on the position B, you can write:

        ⇒ H = x tan(21.4º)

To solve, equal both equations:

Substitute in the equation H = x tan(21.4º)

Rounding to one signficant figure that is 4,000 ft.

5050 i think

step-by-step explanation:

the answer is  

a.

4,624π mm2

step-by-step explanation: