Basic Mathematics
# Length and Area

A rectangular sheet of paper is folded as shown. What is the other side length of the orginal sheet?

A triangle, a square, a pentagon, a hexagon, an octagon, and a circle all have the same perimeter.

Which one has the smallest area?

**Note:** All of the polygons are regular.

and the perimeter of the blue triangle is 30,

and the perimeter of the six-pointed star is 40,

what is the perimeter of the green hexagon?

Find the area of the shaded annulus.

What is the area of the given figure?