### Home > INT2 > Chapter 8 > Lesson 8.4.1 > Problem 8-81

8-81.

Use your findings from problem 8-79 to answer the questions below. Recall that the **diameter** of a circle is a segment with endpoints on the circle that passes through the center. The length of the segment is also called the diameter. Homework Help ✎

What is the area of a circle with radius

units? For a circle, area

. area

units ^{^2}What is the circumference of a circle with diameter

units? For a circle, circumference

. If the area of a circle is

square units, what is its diameter? Use the formula for area of circle and solve for the radius.

units

What is the diameter?If the circumference of a circle is

units, what is its area? Use the circumference formula and solve for the diameter.

What is the radius? Use the radius to calculate the area.