# Thread: Volume and SA of a cylinder.

1. ## Volume and SA of a cylinder.

i have a cylinder here i need to find the volume and the surface area

the cylinder is 4cm base height 15cm

would the volume be 3.14 x 42 x 15 = 753.6 i have to give the answer to 3 significant figures so 754cm.

and would the surface area be

2 x 3.14 x 4 x 15 + 2 x 3.14 x 42 = 194.68 i have to give the answer to 2 siginificant figures so 190cm!

is that right?????

2. Originally Posted by thierryvoomhenry
i have a cylinder here i need to find the volume and the surface area

the cylinder is 4cm base height 15cm

would the volume be 3.14 x 42 x 15 = 753.6 i have to give the answer to 3 significant figures so 754cm.

and would the surface area be

2 x 3.14 x 4 x 15 + 2 x 3.14 x 42 = 194.68 i have to give the answer to 2 siginificant figures so 190cm!

is that right?????
Dear thierryvoomhenry,

The volume is correct. But you should better check the surface area. It should be, 477.28

3. Hmmm, I am pretty sure the formulas are as following:

Therefore, the correct volume is 188.496 or 188 (3 sig figures) and the correct surface area is 213.628 or 214 (3 sig figures)

I think both of your are taking the radius as 4 cm whereas that's the length of the base, which can be used as a diamter but half that is the radius of that cylinder.

Hope this helps!

4. Dear unstopabl3,

Yes you are correct. When he says "the cylinder is 4cm base" it is most probably the diameter.