A circular cone has a diameter of 8 in. and a slant height of 10 in. What is the surface area of the cone to the nearest inch?(1 point)

Responses

302 in.2
302 in. squared

452 in.2
452 in. squared

63 in.2
63 in. squared

176 in.2

1 answer

To find the surface area of a circular cone, we use the formula:

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

where:

  • \( r \) is the radius of the base of the cone,
  • \( l \) is the slant height of the cone.

Given:

  • Diameter of the cone = 8 in, so the radius \( r = \frac{8}{2} = 4 \) in.
  • Slant height \( l = 10 \) in.

Now, we can calculate the surface area:

  1. Calculate the lateral surface area (the curved surface area): \[ \pi r l = \pi \cdot 4 \cdot 10 = 40\pi \]

  2. Calculate the base area: \[ \pi r^2 = \pi \cdot 4^2 = 16\pi \]

  3. Therefore, the total surface area is: \[ \text{Surface Area} = 40\pi + 16\pi = 56\pi \]

  4. Now, we will calculate \( 56\pi \): \[ 56\pi \approx 56 \cdot 3.14 \approx 175.84 \]

Rounding \( 175.84 \) gives us approximately \( 176 \) in².

Thus, the surface area of the cone to the nearest inch is 176 in².