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.

Answer 1

Area of half circle = 1/2 x π x r^2

= 1/2 x 3.14 x 2.5^2

= 9.8125 miles²

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

Density =population/area= 175/9.8125 = 17.83 dolphins/mile²

the population density of the dolphins is 18dolphin/miles²

Answer 2

Density = 9 dolphins / mi^2 This is the result.

Explanation:

Number of dolphins = 175

Radius = 2.5 mi

1. - Calculate the area

Area = pi* r^2

Area = 3.14*2.5^2

Area = 3.14*6.25

Area = 19.625 mi^2

2. - Calculate the density

density = dolphins/mi^2

- Substitution

density = 175 / 19.625

Result

density = 8.9 dolphins/mi^2

Rounding to the nearest whole number

Density = 9 dolphins / mi^2