Sophia Learning
Sophia: Finding a Formula for the Surface Area of a Cone: Lesson 6
This lesson explains how to write a formula for the surface area of a cone.
Sophia Learning
Sophia: Finding a Formula for the Surface Area of a Pyramid: Lesson 5
This lesson explains how to write a formula for the surface area of pyramids. It is 5 of 5 in the series titled "Finding a Formula for the Surface Area of a Pyramid."
University of California
Ucla Mathematics Department : Midpoint Rule
This site from UCLA Mathematics Department explains the Midpoint Rule and how it relates to a double integral and finding surface area.