One side of a regular pentagon is folded back and forth as shown. Are the six red line segments congruent?
Folding a pentagon

One side of a regular pentagon is folded back and forth as shown. Are the six red line segments congruent?
One corner of a rectangular piece of paper is folded as shown. Prove that the red line segments are concurrent.
A unit square paper is folded as shown. What is the red area?
One corner of a rectangular piece of paper is folded back and forth to the opposite side. What is the proportion red : blue?
A rectangle with given side lengths is folded back and forth such that the corner touches the opposite side as shown. What is the minimal shaded fraction?
Divide a rectangular piece of paper in five pieces of equal area. You only have a pair of scissors at your disposal, but you are allowed to make straight folds to guide you.
A rectangle with an inscribed right triangle. What is ac/bd?
A square sheet of paper is folded symmetrically from a corner. If the fold length is 4, what is the area of the triangle formed by the other three corners?
A regular hexagon is folded back and forth along the dotted line. What fraction of the area is yellow?
An equilateral triangle is folded with its left side at right angles with the base. What fraction of the total triangle is shaded?