Question

The captain of a boat knows that a lighthouse on the coast is 100 ft

Answer 1

Answer:

Height of the light house $=7.5\ feet$

Step-by-step explanation:

Distance of light house from boat = 100 ft

Angle of elevation from boat to the top of light house = 2°

Height above water while taking measurement = 4 ft

The figure of the situation is shown below.

For Δ ABC

$\tan2\°=\frac {AB}{BC}$

$\tan2\°=\frac {AB}{100}$

$0.035=\frac {AB}{100}$

Multiplying both sides by 100.

$100\times 0.035=100\times\frac {AB}{100}$

$3.5=AB$

∴ $AB=3.5$

Height of the light house $=3.5+4=7.5\ feet$