# Homework Help: Trouble with this equation

1. Sep 9, 2004

$$P= \frac{2 {\p} G}{3}p^2r^2[\tex] i need to find r = just having trouble where to start! I have tried a few times. just a bit stuck! Any help would great ! Thanks in advance 2. Sep 9, 2004 ### james11 OK lets try again! [tex]P= \frac{2 {\p} G}{3}p^2r^2$$

i need to find r =

just having trouble where to start!

I have tried a few times.

just a bit stuck!

Any help would great !

3. Sep 9, 2004

### jcsd

Divide both sides by p^2 2G/3

4. Sep 10, 2004

### james11

I have divided by this but i don't seem to get the radius i am given

I end up with R = SQUARE ROOT P2G/3

am i on the track or have mixed up the equation

j

5. Sep 12, 2004

### Kelju Ivan

"I end up with R = SQUARE ROOT P2G/3"
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You made a mistake while dividing. You should end up with
$$r^2 = \frac {3P} {2Gp^2}$$

6. Sep 12, 2004

### james11

Yes i have managed to rearrange to and i have that part. The next part of the question ask
to rearrange another equation that is similar to the original equation given but instead it is 2pieG/3*P^2*R^2 and then find R

I have managed to get R = Sqrt3P/2pieGP

any help would be great in pointing me in the right direction

I am not getting the right figure for R so i must messing up this equation
2pieG/3*P^2*R^2

thanks :grumpy:

Last edited: Sep 12, 2004
7. Sep 15, 2004

### james11

I figure it out

My brain must have gone walk abouts for the past week!

j