Question

A cone-shaped megaphone has a radius of 15 centimeters and a slant height of 20 centimeters. A megaphone has an open bottom. What is the lateral surface area of the megaphone, in square centimeters? Use 3.14 for pi.(1 point)
Responses

942 square centimeters
942 square centimeters

1,648.5 square centimeters
1,648.5 square centimeters

1,884 square centimeters
1,884 square centimeters

109.9 square centimeters

1 answer

To find the lateral surface area of the cone-shaped megaphone, you can use the formula:

\[ \text{Lateral Surface Area} = \pi r l \]

where:

  • \( r \) is the radius of the base of the cone,
  • \( l \) is the slant height of the cone,
  • \( \pi \) is approximately 3.14.

Given:

  • \( r = 15 \) cm
  • \( l = 20 \) cm

Substituting the values into the formula:

\[ \text{Lateral Surface Area} = 3.14 \times 15 \times 20 \]

Now, calculating the expression step-by-step:

  1. Calculate \( 15 \times 20 \):

\[ 15 \times 20 = 300 \]

  1. Now, multiply by \( \pi \):

\[ \text{Lateral Surface Area} = 3.14 \times 300 = 942 \]

Thus, the lateral surface area of the megaphone is:

\[ \text{Lateral Surface Area} = 942 \text{ square centimeters} \]

Therefore, the correct answer is:

942 square centimeters.