Question

Finding the surface area of a sphere & the volume for each figure

Answer 1

Surface area of a sphere

Both surface area and volume of a sphere are found using its radius

Radius

It is the distance from its center to its side. In this case

The radius, r is half the diameter:

r = 20m/2 = 10m

Surface area

It is given by the equation:

$4\pi r^2$

we replace r by 10m

$\begin{gathered} \downarrow\text{ since r=10}m \\ 4\pi(10m)^2 \\ \downarrow\text{ since }10^2=100 \\ 4\pi100m^2=400\pi m^2 \end{gathered}$

Using a calculator we have:

$400\pi\cong1256.637$

Rounding the answer to the nearest hundredth (two digits after the decimal point:

1256.637 ≅ 1256.64

Answer: the surface area of the sphere is approximately 1256.64 m²