Finding distance by angle of incident

[aChordate]

Homework Statement

The light in a lighthouse sits 55 m above sea level. The beam of light strikes the water
at an angle of incidence of 63⁰ and illuminates a shipwreck on the ocean floor. If the
water is 17 m deep, what is the horizontal distance from the lighthouse to the shipwreck?

Homework Equations

tan=opp/adj

n₁sinθ₁=n₂sinθ₂

The Attempt at a Solution

tan63=x/55m

x=110m

(1.0)sin(63°)=(1.33)sinθ₂

θ₂=42

tan(42)=opp/17m
opp=15m

15+110m=125m

 

[ehild]

Homework Statement

The light in a lighthouse sits 55 m above sea level. The beam of light strikes the water
at an angle of incidence of 63⁰ and illuminates a shipwreck on the ocean floor. If the
water is 17 m deep, what is the horizontal distance from the lighthouse to the shipwreck?

Homework Equations

tan=opp/adj

n₁sinθ₁=n₂sinθ₂

The Attempt at a Solution

tan63=x/55m

x=110m

(1.0)sin(63°)=(1.33)sinθ₂

θ₂=42

tan(42)=opp/17m
opp=15m

15+110m=125m

Your method is correct, but you do not get the result with three significant digits if you calculate with two digits. The data are given with two digits, use three during the calculations and round off at the end.

ehild