Maths

[bolterixus]

Hey guys I have been looking every where and they only show u how to find the volume of a hemisphere. But I dont know how to find the radius. Does anyone know the formula to find the radius of a hemisphere

 

[Reaper 392]

What information about the hemisphere are you given?

 

[SlyReaper]

Your question is incomplete, and does not make sense as it currently stands.

 

[bolterixus]

I got given the following:

The volume of a hemisphere is 34.2cmcubed. calculate the radius of the hemisphere

 

[Judgeneo]

Measure it.

Failing that, V = 2/3 pi r^3
So r = (3V/2pi)^1/3
or r = C / 2pi

Where r is radius, V is volume and C is circumference

 

[cheesyboy]

V = 4/3 π r^3 (volume of hemisphere)

r^3 = 3πV / 4
r = [cube root] 3πV / 4

 

[Reaper 392]

YOu just need basic algebra to rearrange the volume of a (hemi)sphere equation

V = 2/3 * pi * r³
3V/2pi = r³
cube root(3V/2pi) = r

*edit*
cheesyboy, you started with the volume of a sphere, not a hemisphere

*edit 2*
simplified middle fraction properly now
(still had the end result right)

 

[Mynight]

E=mC2

If that doesn't work what they said above will.

 

[Bloomfield]

http://www.calculatorsoup.com/calculators/geometry-solids/hemisphere.php

 

[Tuppy_Glossop]

volume of hemisphere is 2/3*pi*r^3

so r^3=(3/2)*volume/pi

so r=((3/2)*volume/pi)^(1/3)

r=2.537cm

 

[cheesyboy]

YOu just need basic algebra to rearrange the volume of a (hemi)sphere equation

V = 2/3 * pi * r³
2V/3pi = r³
cube root(3V/2pi) = r

*edit*
cheesyboy, you started with the volume of a sphere, not a hemisphere

Yup, just realised that

 

[bolterixus]

thanks guys. I am awful with volume and all these radius and circumference stuff