# Surface Area of a Cylinder

- Author:
- Whitney Evans, dthurston

**Surface Area of a Cylinder:**The surface area of an object is the number of square units needed to cover all of the surfaces of that object. Let's pull this cylinder apart to see what surfaces we need to cover! Pull the slider along the top from left to right to pull the surfaces of our cylinder apart. After you pull the surfaces completely apart, use the results to discuss the questions below with your shoulder partner.

**Question 1:**What shapes are the three surfaces of a cylinder?

**Question 2:**By pulling this cylinder apart, have we changed the amount of square units needed to cover these faces?

**Question 3:**How are the area of the "net" we end up with on the left and the surface area of our original cylinder related?

**Question 4:**How could we compute the length of the purple edge of our rectangle? (Hint: look at the "other" purple edge in the picture)

**Question 5:**Describe a plan for finding the surface area of a cylinder.