A grid shows a right triangle upper A upper B upper C. The angle of the vertex upper B is at the right angle.

Use trigonometric ratios to solve the following problem. Shaina, who is 5 feet, 6 inches tall, is standing 20 feet from the base of a tree when she sees a pileated woodpecker at the top of the tree. The bird is at an angle of elevation of 68 degrees above Shaina’s line of sight. What is the height of the tree?

(1 point)
Responses

680 inches
680 inches

240 inches
240 inches

66 feet
66 feet

55 feet

1 answer

To find the height of the tree, we can use the information given and apply trigonometric ratios.

  1. Convert Shaina's height: Shaina is 5 feet 6 inches tall. We convert this entirely to inches: \[ 5 \text{ feet} = 5 \times 12 = 60 \text{ inches} \] \[ 5 \text{ feet} 6 \text{ inches} = 60 + 6 = 66 \text{ inches} \]

  2. Identify known values:

    • Distance from Shaina to the base of the tree = 20 feet
    • Angle of elevation to the bird = 68 degrees
    • Height of Shaina = 66 inches (or 5.5 feet)
  3. Determine the total height of the tree: Let \( h \) be the height of the tree in feet above Shaina's height.

    We can use the tangent function, which relates the angle of elevation to the opposite and adjacent sides: \[ \tan(\text{angle}) = \frac{\text{opposite}}{\text{adjacent}} \] In this case, the opposite side is the height of the tree above Shaina (\( h \)), and the adjacent side is the distance from Shaina to the tree (20 feet): \[ \tan(68^\circ) = \frac{h}{20} \] Rearranging gives: \[ h = 20 \cdot \tan(68^\circ) \]

  4. Calculate \( h \): Using a calculator, find \( \tan(68^\circ) \): \[ \tan(68^\circ) \approx 2.4751 \] Now we substitute this back: \[ h = 20 \cdot 2.4751 \approx 49.502 \text{ feet} \]

  5. Total height of the tree: To find the total height of the tree, we need to add Shaina's height (5.5 feet) to the height \( h \): \[ \text{Total height of the tree} = h + \text{height of Shaina} = 49.502 + 5.5 \approx 55.002 \text{ feet} \]

Since the question asks for the height of the tree in feet, rounding it gives approximately 55 feet.

So the height of the tree is: 55 feet.