The equation for the volume of a cylinder is:
V = πr²h
V= volume
r= radius
h= height
In the problem, you are already given the height of 8cm
To find the radius, you have to understand that diameter is a straight line that represents the distance across a circle. The radius is half this distance. To find the radius, divide the value of the diameter by 2.
Radius= 14 ÷ 2= 7cm
Now plug in all your information into the Volume equation and solve:
V = πr²h
V= π × 7² × 8
V = π × 49 × 8
V = π × 392
V = 392π or ≈1231.5