The method of making a regular pentagon from rectangular paper is used in many origami. If you don’t know how to do it yet, you can follow the diagram below to learn it. It’s quite simple!~
First find a rectangular piece of paper, fold it in half, and then fold it as shown in the picture below. The angle β is twice as large as α.
Fold angle β inward in half.
Then fold angle α back.
Cut along the black line.
Expand and a regular pentagonal paper is completed.