Chapter 11.2, Problem 54SR

To determine

To find: the circumference and area of the given figure and round to the nearest tenth.

Answer to Problem 54SR

Circumference $C=19.5\text{cm}$

Area $A=30.18{\text{cm}}^2$ .

Explanation of Solution

Given information: Given figure is a circle of diameter 6.2 cm.

Formula used:

The radius of the circle $=\frac{Diameter}{2}$ .

The circumference of the circle of radius r is:

  C = $2\pi r$ .

The area of the circle of radius r is:

  A = $\pi r^2.$

Calculation:

The radius of the circle $=\frac{Diameter}{2}=\frac{6.2}{2}=3.1\text{cm}$

The circumference of the circle of radius r is:

  $\begin{array}{l}C=2\pi r.\\ r=3.1\text{inch},\pi =\mathrm{3.14.}\\ C=2\times 3.14\times 3.1\\ C=19.5\text{cm}\end{array}$ .

The area of the circle of radius r is:

  $\begin{array}{l}A=\pi r^2.\\ r=3.1\text{inch},\pi =\mathrm{3.14.}\\ A=3.14\times {3.1}^2\\ A=30.18{\text{cm}}^2\end{array}$