Question

Question 10 options:

A marine biologist is researching the population density of dolphins. The marine biologist counts 175 dolphins within a radius of 2.5 miles of a half circle off of Clearwater Beach.

What is the population density of the dolphins?

Use 3.14 for pi, and round to the nearest whole number.

Density = dolphins/mi2

Answer 1

18 dolphins/mi²

Explanation:

area of circle = π x r² = (3.14)(2.5²)/2 = 9.81 miles²

175/9.81 = 17.83 dolphins per square mile

Answer 2

Find the area of the half circle.

Area of half circle = 1/2 x pi x r^2

= 1/2 x 3.14 x 2.5^2

= 9.8125 square miles.

For the density divide the number of dolphins by the area:

Density = 175 / 9.8125 = 17.83

Rounded to nearest whole number the density is 18 dolphins per square mile.