Home > INT2 > Chapter 8 > Lesson 8.4.2 > Problem8-96

8-96.
1. Use what you know about the area and circumference of circles to answer the questions below. Show all work. Leave answers in terms of π. Homework Help ✎

1. If the radius of a circle is 14 units, what is its circumference? What is its area?

2. If a circle has diameter 10 units, what is its circumference? What is its area?

3. If a circle has circumference 100π units, what is its area?

4. If a circle has circumference C, what is its area in terms of C?

To calculate the area of a circle use πr2, for the circumference use 2πr.

area = 196π
circumference = 28π

Use the formulas given in part (a). What is the radius of this circle?

100π = 2πr
Solve for the radius then use the radius to calculate the area.

$\frac{C}{2\pi}=r$

$A=\frac{\pi C^2}{4\pi^2}=?$