To calculate the lateral area of a cylinder, we can use the following formula.
L=2π rhIn this formula, r is the radius of the base and h is the height of the cylinder. We know that the diameter d of the base is equal to 18inches and is exactly twice as long as its radius.
d=2r ⇒ r= d2= 182=9in.
Substituting r with 9 and h with 20 into the formula, we can find L.
We know that lateral area is 360π or about 1131.0 in^2.
Surface Area
To calculate the surface area of a cylinder, we can use the following formula.
S=L+2π r^2
In this formula, L is the lateral area of the cylinder and r is the radius of the base.
Substituting L with 720π and r with 9 into the formula, we can find S. Let's do it!
