Find the surface area of a cone with a radius of 5 cm and a slant height of 10 cm.

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

Step 2 ：Substituting the given values into the formula gives us \(\pi (5)(5 + 10)\).

Step 3 ：Calculating that gives us \(75\pi \, cm^2\).