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 10 units?
What is the circumference of a circle with diameter 7 units?
If the area of a circle is 121π square units, what is its diameter?
If the circumference of a circle is 20π units, what is its area?
For a circle, area = r2 · π.
area = 102·π = 100π units2
For a circle, circumference = d·π.
Use the formula for area of circle and solve for the radius.
r = 11 units
What is the diameter?
Use the circumference formula and solve for the diameter.
What is the radius? Use the radius to calculate the area.