Determine the surface area of a cone if the diameter of the base is 14 ft., and the slant height of the cone is 19 ft. Use π = 3.14 and round your answer to the nearest hundreth. (1 point)

1 answer

To determine the surface area of a cone, we can use the following formula:

\[ \text{Surface Area} = \pi r^2 + \pi r l \]

where \( r \) is the radius of the base, \( l \) is the slant height, and \( \pi \) is a constant (approximately 3.14 in this case).

  1. Calculate the radius \( r \): The diameter of the base is given as 14 ft. Therefore, the radius \( r \) is: \[ r = \frac{\text{diameter}}{2} = \frac{14}{2} = 7 \text{ ft} \]

  2. Identifying the slant height \( l \): The slant height \( l \) is given as 19 ft.

  3. Calculate the surface area:

    • First, compute the area of the base: \[ \pi r^2 = \pi (7)^2 = \pi \times 49 = 3.14 \times 49 = 153.86 \text{ ft}^2 \]

    • Next, compute the lateral surface area: \[ \pi r l = \pi \times 7 \times 19 = 3.14 \times 7 \times 19 \]

    First, calculate \( 7 \times 19 \): \[ 7 \times 19 = 133 \] Now, compute: \[ \pi r l = 3.14 \times 133 = 417.62 \text{ ft}^2 \]

  4. Combine the areas: Now, add the area of the base and the lateral surface area: \[ \text{Surface Area} = \pi r^2 + \pi r l = 153.86 + 417.62 = 571.48 \text{ ft}^2 \]

Therefore, the surface area of the cone is approximately:

\[ \boxed{571.48} \text{ ft}^2 \]