6.5 Volume of Spheres

6.5 Volume of Spheres

• Similarly to cylinders and cones, we have dealt with trying to find the area of a circle at some point in trying to find volume of these somewhat circular shapes.

• However, with spheres, we are still using the radius and pi, but the formula changes just a little

Volume of Sphere

• With spheres, we still need the radius; in this case, it's 8.

• However, instead of squaring it like we are used to in the past, we actually cube it (8^3)

• Next we can still multiply it times pi.

• And then our last step is to multiply all of that by 4/3...so it will look something like this

•  $V=\frac{4}{3}\pi r^3$  

•  $V=\frac{4}{3}\pi\left(8\right)^3\rightarrow2144.7$  

Let's try another one

• Do we have the radius? (Or do we have the diameter, but we can find the radius from that?)

• Plug this radius into our formula

• Try this on your own before clicking to see the answer

•  $V=38792.4$  

Multiple Choice

What is the formula to find the volume of a cone?

• $\frac{4}{3}\pi r^3$

• $r^2\pi h$

• $\frac{r^2\pi h}{3}$

Fill in the Blanks

Find the volume of this sphere. Round to the nearest tenth.