The square possesses **the following characteristics**: All of the attributes of a rectangle are applicable (the only one that matters here is that diagonals are congruent). By definition, all sides are congruent. By definition, all angles are right angles.

A square is a kind of rectangle that has all of the attributes of rectangles. These are applicable to any parallelogram, including rectangles and squares:

- Opposite sides are parallel.
- Opposite sides are congruent.
- Opposite angles are congruent.
- Consecutive angles are supplementary.
- Diagonals bisect each other.

A square must have two opposite sides that are parallel, all sides that are congruent, and four right angles. A rectangle is also defined as a parallelogram with four right angles, whereas a square is defined as a parallelogram with four congruent sides and four right angles. These definitions imply that a rectangle can be a sub-type of a square, but not every square is necessarily a rectangle.

It is important to understand that both a rectangle and a square can have any number of sides, but they must always have equal lengths for them to be considered the same shape. For example, a rectangle with one side length of 7 inches and one side length of 10 inches would not be the same shape as a square with sides of 7 inches and 10 inches because they have **different numbers** of sides.

There are several ways to measure the angles of a rectangle. Angles can be measured in degrees or radians. There are 360 degrees in a circle so angles can be thought of as fractions of a circle. In mathematics and physics, angles are measured in degrees, which are numbered starting from 0 at the top left corner and going around the circle until it returns there. The angle between **two lines** is measured by placing a third line across **those lines** at right angles (90 degrees) and counting the number of degrees that it takes to go from one line to the other. This number is the angle between the two lines.

A square is also a parallelogram with 90-degree intersecting sides. As a result, all of its sides are congruent. When both sets of **opposing sides** of a rectangle are the same length, it is a square. This indicates that a square is a subset of the rectangle and is, in fact, a rectangle.

Regular quadrilateral polygons are squares. Their sides are all the same length, and their angles are all right angles. They are rectangles with sides that are all the same length. The term "square" is used for these shapes because they are equal in size to **any other square-shaped object**.

A polygon with four straight lines is called a quadrilateral. These include triangles as well as squares. A triangle has **three sides** and two angles, while a square has four sides and four angles. Triangles and squares are the only regular polygons besides circles. Every other regular polygon contains either more triangles or more squares than circles. For example, there are five times as many triangles as circles in a decagon (10-sided figure).

There are two ways of numbering the sides of a quadrilateral. Either number each side from 1 to 4 and then number the pairs of sides that meet at right angles, or start with the top side and work your way down counting both up and down. For example, you could say the side opposite the 3 is called the 5th side or that it has been numbered from bottom left to top right. There is no right or wrong way to do this, but some people like to use numbers for the sides of the quadrilateral that match the position of the corresponding point on a grid.