The given solid is a cone with a diameter of 20 millimeters and a slant height of 42 millimeters. To calculate the surface area of a cone, we can use the known formula where r is the radius of the base and l is the slant height of the cone.
S=π rl+π r^2We know that the diameter of the cone's base is 20 millimeters. By dividing by 2, we get the radius of the base.
r=20/2 ⇒ r = 10mm
We are told that the slant height of the cone equals 42 millimeters. By substituting r with 10 and l with 42 into the formula, we can calculate S.
