A designer is creating a modern art sculpture of an hourglass out of steel, to be on display at the town library. The hourglass is made by two cones meeting at the top point. The designer wants to know how many square feet of steel is needed for the outside of the sculpture, if the slant height of each cone is 5 feet and the diameter is 8 feet. Use 3.14 for pi.(1 point) Responses 653.12 square feet 653.12 square feet 113.04 square feet 113.04 square feet 326.56 square feet 326.56 square feet 226.08 square feet

1 answer

To find the surface area of the hourglass sculpture made of two cones, we need to calculate the lateral surface area of one cone and then double it since there are two identical cones.

The formula for the lateral surface area \(A\) of a cone is given by:

\[ A = \pi r l \]

where \(r\) is the radius of the base of the cone and \(l\) is the slant height of the cone.

  1. Find the radius \(r\):

    • The diameter of the cone is 8 feet, so the radius \(r\) is: \[ r = \frac{8}{2} = 4 \text{ feet} \]
  2. Use the given slant height \(l\):

    • The slant height is given as 5 feet.
  3. Calculate the lateral surface area of one cone: \[ A = \pi r l = 3.14 \times 4 \times 5 \] \[ A = 3.14 \times 20 = 62.8 \text{ square feet} \]

  4. Calculate the surface area for both cones: \[ \text{Total surface area} = 2 \times 62.8 = 125.6 \text{ square feet} \]

It seems that this result does not match any of the options provided in the question. Thus, let's review the calculations.

However, if the question asks for the surface area without including the base of the cones (as they meet at the point), the total surface area of the hourglass sculpture will be:

\[ \text{Total surface area} = 2 \times 62.8 = 125.6 \text{ square feet} \]

None of the provided options match this calculation. It’s also possible that there was a misunderstanding about the expected surface area calculation setup (like if including the base area is required).

Please confirm whether the bases are included or if there is any other detail.