How do you find the radius of a cylinder

In this problem i was given the HEIGHT and VOLUME and i need to find the RADIUS
H=6.4 and V=219^2. how do i find the radius? whenever i try i can'y get the right answer. and the answer should be 3.3
HELP

The volume is probably 219 and not 219^2.

V = pi* r^2 * H
219 = pi * r^2 * 6.4
r = sqrt(219/(6.4*pi))
r = 3.3

you need to figure out the volume of a cylinder

V of a cylinder = area across the top x the height

area across the top = cross sectional area
A = pi*r^2

V = pi*r^2 * h
solve for r

r^2 = V/(pi*h)

r = sqrt(V/(pi*h))

thats it all the rest is number

r = sqrt(219/(pi*6.4))
r = sqrt(10.89)
r = 3.3 m

I think your question should say V = 219, not 219^2. (Did you mean 219 cm^3?)

The volume = height x cross-sectional area
V = HA
219 = 6.4A
A = 219/6.4 = 34.2

The Area, A = pi.R^2
R^2 = A/pi
= 34.2/3.14
= 10.9

R = square_root(10.9)
= 3.3

If you were given units (eg. cm) don't forget to include them as part of the answer, e.g. 3.3cm.

Happy new year!

The equation for the volume of a cylinder is V = pi*r^2*h.
You can rearrange that to express the radius in terms of the other variables:
r = sqrt(V/(pi*h))

From there you can go on to solve for the radius.

volume = height times the(pi times radius squared)
substitute
219^3 = 6.4 x 3.14 x r^2

Then solve for r

(pi x r^2) x h = v
r^2=v/hxpi
r^2=219/6.4xpi
r^2=219/20.096
r^2=10.898
r=srt10.898
r=3.3

Please note I used 3.14 as pi

219=6.4πr^2
219/6.4π=r^2
10.90=r^2
3.3=r