A cylinder is unfolded into its net. What is the length of the rectangle in that net equal to?

1. Unfolding a cylinder gives two identical circles and one rectangle. 2. The two circles are the flat top and bottom faces. 3. The rectangle is the curved wall of the cylinder rolled out flat. 4. That wall wraps exactly once around the circular base. 5. The length of the rectangle is therefore equal to the circumference of the circles. 6. The radius and the diameter are both far too short to wrap all the way around, which is the trap here. _Source: Siyavula Mathematics Grade 10 (Everything Maths, CC BY 4.0), Chapter 13: Measurements_