Question

Sand dollars are animals that live buried in the sand of shallow coastal waters. The thin circular body of a sand dollar is usually 2 to 4 inches wide. Find the area of a sand dollar that is 3 inches wide.

Answer 1

Area = πr^2

The diameter is twice the area.

The diameter is the width of a circle.

This means the radius is (3/2).

A = π(3/2)^2

A = π(9/4)

A = 9π/4

A = 7.0685834706

A = 7.07

Answer 2

The area of a sand dollar that is 3 inches wide is
`7.0686 inch^2`

Explanation:

Width of sand dollar's circular body = d = 3 inches

Radius of the sand dollar's circular body = r

`r=(d)/(2) = (3 inch)/(2)=1.5 inches`

Area of circle =
`\pi r^2`

So, the area of a sand dollar that is 3 inches wide:

`A=3.14* (1.5 inch)^2=7.0686 inch^2`

The area of a sand dollar that is 3 inches wide is
`7.0686 inch^2`