Surface area of cones practice

What is the surface area in square meters of a cone with a slant height of 8 meters and a radius of 5 meters use 3.14 for pi and round the nearest tenth if necessary

1 answer

The surface area \(A\) of a cone can be calculated using the formula:

\[ A = \pi r (r + l) \]

where \(r\) is the radius, \(l\) is the slant height, and \(\pi\) is approximately 3.14.

Given:

  • Radius \(r = 5\) meters
  • Slant height \(l = 8\) meters

Now, substitute the values into the formula:

\[ A = 3.14 \times 5 \times (5 + 8) \]

First, calculate \(5 + 8\):

\[ 5 + 8 = 13 \]

Now substitute this value back into the surface area formula:

\[ A = 3.14 \times 5 \times 13 \]

Calculating \(5 \times 13\):

\[ 5 \times 13 = 65 \]

Now, calculate \(A\):

\[ A = 3.14 \times 65 \]

Calculating \(3.14 \times 65\):

\[ 3.14 \times 65 = 204.1 \]

Thus, the surface area of the cone is approximately

\[ \boxed{204.1} \text{ square meters.} \]