Find the surface area of a cone with a radius of 3 cm and a slant height of 5 cm.

Step 1 ：Step 1: Recall the formula for the surface area of a cone, which is \(\pi r(r + l)\), where \(r\) is the radius and \(l\) is the slant height.

Step 2 ：Step 2: Substitute the given values into the formula. That is, \(\pi * 3(3 + 5)\).

Step 3 ：Step 3: Simplify the expression to get the surface area. That is, \(\pi * 3 * 8\).