What are the two examples of quadrilaterals


This picture shows the main regular quadrilaterals. Depending on the shape, they also have different names.

In geometry, a square is a figure of the plane. It always has four corners and four sides. A square can still have different shapes because the sides and angles can be of different sizes. The lines that connect the opposite corners of a square are called diagonals.

If the sides or angles of a quadrilateral meet special conditions, then the quadrilaterals have specific names. There are trapezoids, parallelograms, diamonds, dragon squares, rectangles or squares. If none of these apply to a square, then it's called an irregular square.

With a trapezoid, two opposite sides are parallel and two can somehow lie, no matter how. If both pairs of sides are parallel, one speaks of a parallelogram. If both pairs of sides are parallel to each other and all sides are of the same length, then the square is called a diamond or rhombus.

If the diagonals are at right angles to each other, i.e. ninety degrees, one speaks of a dragon square. If all corners of a square are right-angled, this is called a rectangle. A rectangle with four sides of equal length is called a square.

Why is a square also a trapezoid?

There are often several names for quadrilaterals. But so that you know as exactly as possible what the square looks like, you usually take the name that best describes it.

If you have a square in front of you, then of course it is also a trapezoid: two opposite sides are parallel. The other two sides of the trapezoid can be in any position, so in special cases they can be parallel to each other. In this way you can name many quadrilaterals multiple times.

A square can therefore be viewed as a special case of a trapezoid, a parallelogram, a dragon square, a diamond (a rhombus) and a rectangle. Nevertheless one says square because that is the clearest description. The square is the most special rectangle.

A rectangle is also a parallelogram and also a trapezoid. But it is not a diamond, for example, because not all four sides are the same length. A diamond is also a parallelogram and a parallelogram is a special case of a trapezoid.

  • This is an irregular square.

  • The logo of the football club Werder Bremen uses a diamond.

  • Many things are in the shape of a square, like this bowl.