Question

A boat is heading towards a lighthouse, whose beacon-light is 131 feet above the
water. From point A, the boat's crew measures the angle of elevation to the beacon,
5°, before they draw closer. They measure the angle of elevation a second time from
point B at some later time to be 21°. Find the distance from point A to point B.
Round your answer to the nearest tenth of a foot if necessary.

Answer 1

Answer:

Step-by-step explanation:

Assuming a flat earth

initial measurement

tan5 = 131 / d₁

d₁ = 131/tan5 = 1,497.3368... ft

d₂ = 131/tan21 = 341.2666674...ft

distance from A to B

1497.3368 - 341.26666 = 1,156.1 ft

Rather daring to specify to the answer to the nearest tenth of a foot when no given measurement accuracy is even close to that same precision.