Chapter 12, Problem 20CUR

To determine

To find: The surface area of sphere to the nearest square centimeter.

Answer to Problem 20CUR

The surface area of sphereis $10{\text{cm}}^2$ .

Explanation of Solution

Given information:The sphere has a diameter $1.8\text{cm}$ .

Calculation:

The formula to find the surfacearea $\left(SA\right)$ of the sphereis:

  $SA=4\pi r^2$

Here, $r$ is the radius of sphere.

It is known that the radius is half of the diameter. So, the radius of the sphere is:

  $\frac{1.8\text{cm}}{2}=0.9\text{cm}$

Substitute 0.9 cm for $r$ in the above formula.

  $\begin{array}{c}SA=4\pi {\left(0.9\text{cm}\right)}^2\\ =4\times 3.14\times 8.1{\text{cm}}^2\\ =10.1736{\text{cm}}^2\\ \approx 10{\text{cm}}^2\end{array}$

Therefore, the surface area of sphere is $10{\text{cm}}^2$ .