## jimmy2016 2 years ago V=(1/3)pie r^2h solve for r

1. Romero

that means that we want r by itself. So everything on the right hand side must go away except the r

2. Romero

$V=\frac{1}{3}\pi r^2h$ What do you want to get rid of first?

3. jimmy2016

um 1/3

4. Romero

great that's division. Opposite of division is multiplication so we have to multiply both sides by 3$3*V=3*\frac{1}{3}πr^2h$$3*V=πr^2h$

5. Romero

now we must get rid of pi and h so we have to divide both sides by pi and h....what do you get then?

6. jimmy2016

y by three

7. Romero

can you write it again?

8. jimmy2016

|dw:1343255379829:dw|

9. Romero

$\frac{3∗V}{\pi h }=\frac{πhr^2}{\pi h}$

10. Romero

great now we need to square root both sides.

11. jimmy2016

i dont know how

12. Romero

ok square root takes away the squared part in r^2 watch $\frac{3V}{\pi h}=r^2$$\sqrt{\frac{3V}{\pi h}}= \sqrt{r^2}$$\sqrt{\frac{3V}{\pi h}}= r$

13. Romero

but wait we square root both sides so we need the plus or minus$\pm \sqrt{\frac{3V}{\pi h}} =r$

14. jimmy2016

huh

15. jimmy2016

what does that mean

16. jimmy2016

so whats the answer because i got confused

17. Romero

it's that. You have two answers one that is positive and one that is negative

18. Romero

that's what this sign means$\pm$

19. jimmy2016

ohhhhhh okay wow thanks i didnt know that I am just going to high school so this is new