A cylinder has a height of 6 meters and a diameter that is 6 times the measure of the height. Using 3.14 for pi, which of the following can be used to calculate the volume of the cylinder?

(3.14)(36m)2(6m)
(3.14)(18m)2(6m)
(3.14)(6m)2(36m)
(3.14)(6m)2(18m)

Question

A cylinder has a height of 6 meters and a diameter that is 6 times the measure of the height. Using 3.14 for pi, which of the following can be used to calculate the volume of the cylinder?

(3.14)(36m)2(6m)
 (3.14)(18m)2(6m)
 (3.14)(6m)2(36m)
 (3.14)(6m)2(18m)

word2 · Answer

my answer is A

phi · Answer

volume is area of the base times the height
the base is a circle with a *diameter* of 36
what is the radius of the circle ?
area of the base is pi * r^2

kinged · Answer

It's not A. Take care of the diameter and radius.

word2 · Answer

why would it not be A? the measurement of  the diameter is 6 times the high , that means that the diameter is 36 right?

kinged · Answer

Because you don't use the diameter in this formula.

word2 · Answer

Okay so then that means that it is C

phi · Answer

what is the radius of the base ?  any idea ?

word2 · Answer

no idea

kinged · Answer

Option C has radius set as 6. Is that right?

phi · Answer

the radius is half the diameter
if the diameter , what is the radius ?

word2 · Answer

6 ?

phi · Answer

if the diameter is 36, what is the radius ?

word2 · Answer

18

kinged · Answer

Hey! Right.

phi · Answer

yes, r= 18

if you put 18 into the formula for the area of a circle
pi r^2
what does it look like ?  (in other words, erase the r, and put in 18)

word2 · Answer

v = 3.14 * 18^2 *6 ?

kinged · Answer

Yep.

phi · Answer

which choice is that ?

word2 · Answer

thank you everyone !

word2 · Answer

that's choice B

phi · Answer

yes.  as (you know) the height is 6  and the volume is area times height
so  3.14 * (18)^2  (that is the are) * 6 or
3.14 * (18)^2 * 6

word2 · Answer

okay thanks again