Question

Two walls of a canyon form the walls of a steady flowing river. From a point on the shorter wall, the angle of elevation to the top of the opposing wall is 20° and the angle of depression to the bottom of the opposing wall is 320 feet. Using the appropriate right triangle solving strategies, solve for the following: (Do not round intermediate calculated values. Only the final answer should be rounded to one decimal place.)

Answer 1

x is approximately 226.3 feet

y is approximately 308.6 feet

z is approximately 226.3 feet

Explanation:

The given parameters of the walls are;

The angle of elevation from the top of the shorter wall to the top of the opposing wall, θ₁ = 20°

From the diagram, the angle of depression from the top of the shorter wall to the bottom of the opposing wall, θ₂ = 45°

The distance from the bottom of the shorter wall to the base of the opposing wall, l = 320 feet

x = The height of the shorter wall = l × sin(θ₂)

∴ x = 320 feet × sin(45°) = 320 feet × (√2)/2 = 160·√2 feet ≈ 226.3 feet

∴ x ≈ 226.3 feet

By observation, we have;

y = x + z × tan(θ₁)

Where;

z = l × cos(θ₂)

∴ y = 160·√2 + 320 × cos(45°) × tan(20°) ≈ 308.6

y ≈ 308.6 feet

z = l × cos(θ₂)

∴ z = 320 × cos(45°) = 160·√2 ≈ 226.3

z ≈ 226.3 feet.