Answer: the first part is the area of the base: πr²
You take the radius given, (or half of the diameter given) square that and multiply by the value of Pi, commonly 3.14 or 3.1416
The second part is the area of the lateral surface. πrh That is the radius times π times the height of the cone.
Explanation:
The formula as shown is confusing to me. It is better to show exponents with superscript if possible, or use the caret ^ [shift + 6] on a keyboard before the 2.
The second part is the area of the lateral surface. πrh That is the radius times π times the height of the cone. (using h instead of l seems less confusing as lower case L looks like 1 in some fonts) But people do use πrl I realize.
Add the two surface areas together to get the total surface area of the cone.