In order to even start with solving the volume of the tree trunk, you need to find the radius first.
By using the formula "r = C/2π", you can find the radius. The C stand for the circumference of the redwood tree trunk.
r = 20/2π
r = 10π
You do not need to continue any further because the question does no require you to solve for pi.
Now you can use the cylinder volume formula (V = πr^2*h) and find the approximate volume of the redwood tree trunk.
V = π10^2*100
V = π100(100)
V = 10,000π feet^3
The approximate volume of the redwood tree trunk is 10,000π ft^3
The tree trunk is a cylinder. The volume formula for a cylinder is πr²h where r and h are the radius and height respectively. Since the circumference is 20π, that means that the diameter is 20 which makes the radius 10. Now that we know the value of the radius and height, we can write:
πr²h = π * 10² * 100 = 10,000π ft³
Tree trunk is in the shape of cylinder.
Circumference = 20π ft
2πr = 20π
h = 100 ft
= π * 10 * 10 *100
= 10,000π ft³