Closed figures created with straight and curved lines are geometric shapes. Some of the geometric shapes have special names. Triangles, squares, rectangles, and circles are the most common geometric shapes.
A triangle is a closed geometric shape formed by joining three straight lines. Triangle has three corners and three sides.
A square is a closed geometric shape formed by joining four lines of equal length. A square has four corners and four sides. All of its sides are of equal length.
A rectangle is a closed geometric shape formed by combining four lines. A rectangle has four corners and four sides. Opposite side lengths are equal.
You can see many circles around such as the basketball hoop, or a coin. A circle has no sides or corners. This is the most important feature that distinguishes a circle from other geometric shapes.