The rotation of a triangle will form a cone. The surface area of a cone is calculated through the equation,
SA (cone) = πrl + πr²
Hence, for this item the best answer would be cone with surface area a = π.r.l + π.r2, the third choice.
Answer:
See Explanation
Step-by-step explanation:
Given
The question is incomplete, as the cylinders are not given.
Required
The cylinder with greater volume
To answer this question, I will assume the following dimensions.
<u>Cylinder 1</u>


Cylinder 2


Volume is calculated as:

When the radius is reduced by 2, the formula becomes

For the first cylinder, we have:





For the second cylinder, we have:





Cylinder 2 has a greater volume because 392.5 > 282.6
<em>Note: Irrespective of the dimension of the cylinders, the above step works fine.</em>