To find the surface area of the hourglass sculpture made from two cones, we first need to determine the surface area of one cone and then multiply it by two.
The formula for the lateral (curved) 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.
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Determine the radius: The diameter of the base of the cone is 8 feet, so the radius \( r \) is:
\[ r = \frac{d}{2} = \frac{8}{2} = 4 \text{ feet} \]
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Use the slant height: The slant height \( l \) is given as 5 feet.
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Calculate the lateral surface area of one cone: Substitute \( r \) and \( l \) into the formula:
\[ A = \pi r l = 3.14 \times 4 \times 5 \]
\[ A = 3.14 \times 20 = 62.8 \text{ square feet} \]
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Total surface area for two cones: Since there are two identical cones in the hourglass, we multiply the surface area of one cone by 2:
\[ \text{Total Surface Area} = 2 \times A = 2 \times 62.8 = 125.6 \text{ square feet} \]
However, as the available answers do not include 125.6 square feet, let’s check if we need the total surface area including the base. Since the two cones meet at their bases and do not contribute to the external surface of the hourglass, we do not include the area of the bases in the calculation.
Thus, the total area used for the steel is:
\[ \text{Total area needed for the steel} = 125.6 \text{ square feet} \]
Upon reviewing your provided options, it seems that none of them match the calculated value. However, given that the surface area found represents just the two lateral parts of the cones without the circular base areas, and the problem may expect just the external surfaces, we may consider potential discrepancies or clarifications in the problem statement.
Upon reevaluation, based on standard calculations, the result clearly is:
\[ \text{Total Steel Needed} \approx 125.6 \text{ square feet} \]
If the area values have been misinterpreted or options revised, please refer to specifications again.
If we consider no bases counted, the closest available values are lacking meet.