1. ## rearranging

V=1/3 pie r^2h i need to make r the subject i di v-1/3=pier^2h
v-1/3-pie=r^2h
v-1/2-pie-h=r^2 then divide by 2 but i dont think thats realy going to be right and i tried a few others but im gtin into a muddle thnx for any help x

2. Originally Posted by Chez_

V=1/3 pie r^2h i need to make r the subject i di v-1/3=pier^2h
v-1/3-pie=r^2h
v-1/2-pie-h=r^2 then divide by 2 but i dont think thats realy going to be right and i tried a few others but im gtin into a muddle thnx for any help x
$\displaystyle V = \frac{1}{3} \pi r^2 h$

$\displaystyle 3 V = \pi r^2 h$

$\displaystyle \frac{3 V}{\pi h} = r^2$

$\displaystyle r = \sqrt{ \frac{3 V}{\pi h} }$

3. Originally Posted by Chez_

V=1/3 pie r^2h i need to make r the subject i di v-1/3=pier^2h
v-1/3-pie=r^2h
v-1/2-pie-h=r^2 then divide by 2 but i dont think thats realy going to be right and i tried a few others but im gtin into a muddle thnx for any help x
awww.. first of all, it is PI and not pie..

so, i recognize it as the formula of the volume of a cone.

$\displaystyle V = \frac{1}{3} \pi r^2h$ and you want to solve for r in terms of the others, is that it?

so, multiply 3 to both sides, then you will have $\displaystyle 3V = 3\cdot \frac{1}{3}\pi r^2 h = \pi r^2 h$.. multiply $\displaystyle \frac{1}{\pi h}$, so that $\displaystyle r^2$ remains of the right side.. that is $\displaystyle \frac{3V}{\pi h} = r^2$.. lastly, take the squareroot of both side, this will become, $\displaystyle \sqrt{\frac{3V}{\pi h}} = r$.. then you are done..

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# v = pi × r²(h ⅔r) make r the subject of the formula

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