Question

Find the volume of a hemisphere with a diameter of 7 cm. Use pi = 3.14 and round to the nearest hundredth. Show your work for credit.

https://sevenstar.brainhoney.com/Resource/48547922,0/Assets/flvs/geometry_v8_gs_lrc-3053-xml/res0041/07_12_04.gif

Answer 1

Do you know the formula for the volume of a sphere?

Answer 2

no i do not

Answer 3

Alright, well it's one you should memorize:\[4/3*\pi*r^3\]

Answer 4

If that's the formula for a sphere, what should be the formula for a hemisphere?

Answer 5

2 π r2 = 1062

Answer 6

Let's try that again. A hemisphere is half of a full sphere. If the equation above is the volume of a sphere, then the volume formula of a hemisphere should be half of that, right?

Answer 7

right

Answer 8

So what would be the formula for a hemisphere again?

Answer 9

I really don't know when it comes to math I'm not good at it

Answer 10

@agent0smith

Answer 11

\[\frac{ 4/3*\pi*r^3 }{ 2} = 2/3*\pi*r^3\]

Answer 12

Using the diameter = 7, what's the radius?

Answer 13

i don't know

Answer 14

\[radius = \frac{ diameter }{ 2 } = \frac{ 7 }{ 2 } = 3.5\]

Answer 15

what is the next step or is that the final step

Answer 16

You have the radius, r, now just plug in 3.5 into the equation \[2/3 * \pi * r^3\]

Answer 17

And that will give you the volume, which is what you need.