Can you clarify when to half the diameter when finding volume of cylinder? I had the following problem:

1. Picture of cylinder with base of 48cm (no dotted lines) and height of 7cm.

I thought i would solve by using V = 3.14(24)^2 (7) = 12,660.5 cubic meters.

According to the teacher's answer sheet, the correct answer is 336 cubic meters using V = Bh or 48(7).

Do I consider taking half of the base only if it's represented by dotted lines?

2 answers

V = pi*r^2*h = 3.14*24^2*7 = 12,660.5 cm^3(Not m^3).

V = B*h, B=Area of the base, V=pi*r^2*h

48 is not the area of the base; it is the diameter of the base.

Diameter*height = Square units.

Diameter/2 = Radius. So you take 1/2 of
the diameter to get the radius.

I hope this helps.
Correction: In your case, 48 is the
area of the base:

V = B*h = 48m^2 * 7m = 336 m^3 or 336 cubic meters.

Again, take half of the base only when it is the diameter.