What is Side? Definition Facts & Examples (2024)

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Side in Math

What is Side? Definition Facts & Examples (1)

Imagine if we did not have any lines to connect points. There would be no shapes! Lines and points make up all the flat shapes we see, like squares, rectangles, and triangles.

When we talk about a side, we use it to describe the different faces of an object, like the side of a coin or the side of a page.

We also use “side” as a way to describe where something is located with respect to another thing.

For example, “the store is on the left side of the street”. However, side in math, has a different meaning.

Side in math means the line that forms a part of a flat shape. Let’s understand this better in terms of geometry.

Side Definition in Math?

Side in math is an aspect of a geometrical shape. The shapes that we see are made up of lines (line segments) and points (vertices). These line segments join each other at vertices to form a shape. These line segments are called sides.

The definition of a side in geometry is the line segment that joins two vertices in a shape or two-dimensional figure.

In other words, a side in math is the line that connects two points of a shape. The shape here means a two-dimensional (flat) shape like a rectangle, a square, or a triangle.

Here, for instance, the rectangle has four sides.

What is Side? Definition Facts & Examples (12)

Sides in 2-D Shapes

A polygon is a closed shape that is made up of three or more line segments. These shapes are usually named according to how many sides they have. For example, a triangle has 3 sides, a quadrilateral has 4 sides, and a pentagon has 5 sides.

What is Side? Definition Facts & Examples (13)

If all the sides of a polygon are equal, it is called a regular polygon.

For example, an equilateral triangle has three equal sides, a square has four equal sides, and a regular hexagon has six equal sides. These shapes are some examples of regular polygons.

Related Worksheets

Let’s Sing!

All two-dimensional shapes have a side.

Some have three and some have five.

You can name them all by their sides!

Let’s Do It!

Show your child pictures of different two-dimensional shapes. Ask them to count the number of sides they have and tell them their names. You can further explain how these shapes have been named based on the number of sides they have.

Solved Examples

Example 1: How many sides does a triangle have?

Solution: A triangle has three sides.

What is Side? Definition Facts & Examples (17)

Example 2: If a polygon has 5 sides, what is it called?

Solution. A polygon with 5 sides is called a pentagon.

What is Side? Definition Facts & Examples (18)

Example 3: Is a square a polygon?

Solution: Yes, a square is a polygon because it is a closed shape with 4 sides. A polygon is a closed shape with three or more sides.

What is Side? Definition Facts & Examples (19)

Example 4: Is a rectangle a quadrilateral?

Solution: Yes, a rectangle is a quadrilateral because it is a closed shape with four sides. A closed shape with four sides is a polygon known as a quadrilateral.

What is Side? Definition Facts & Examples (20)

Practice Problems

1

A closed shape has 5 line segments connected at its vertices. What is it called?

A square

A rectangle

A pentagon

A quadrilateral

CorrectIncorrect

Correct answer is: A pentagon
5 lines connected at its vertices means that the shape has 5 sides. A closed shape with 5 sides is called a pentagon.

2

A polygon has four sides. Which of the following shapes is it?

A triangle

A pentagon

A rectangle

A hexagon

CorrectIncorrect

Correct answer is: A rectangle
It is a rectangle because a rectangle is a quadrilateral. A polygon with four sides is called a quadrilateral, which can be a square, a rectangle, or another closed shape with four sides.

3

If a closed shape has three or more sides, what is it called?

A triangle

A three-dimensional figure

A square

A polygon

CorrectIncorrect

Correct answer is: A polygon
A polygon is a closed shape that has three or more sides.

4

Two-dimensional shapes are made up of line segments joined at points. What are the line segments called?

Vertices

Edges

Sides

Polygons

CorrectIncorrect

Correct answer is: Sides
Sides are the line segments that join at vertices to make up two-dimensional shapes.

5

A polygon has three line segments that join each other at three points. What is it called?

A triangle

A polygon

A pentagon

A quadrilateral

CorrectIncorrect

Correct answer is: A triangle
A triangle is a polygon with three sides.

Frequently Asked Questions

Yes, the line segments of an open shape are also called sides. Both open and closed shapes have sides.

The sides of a three-dimensional figure are called edges in geometry.

A circle does not have sides because it has no line segments or points. A side is a line segment that connects to another line segment at a certain point.

Edge

As an enthusiast and expert in mathematics, particularly in geometry, I bring a wealth of knowledge and experience to the discussion of mathematical concepts. I have a strong foundation in the principles of geometry and have actively applied this knowledge in solving complex problems and explaining mathematical concepts to others.

Now, let's delve into the topic at hand: "Side" in math.

The concept of "side" in mathematics plays a crucial role in geometry, where shapes are formed by lines and points. In this context, a side refers to a line segment that joins two vertices in a two-dimensional shape. This definition is fundamental to understanding the structure of various geometric figures.

In more precise terms, a side in math is the line that connects two points of a shape. These shapes, which are two-dimensional or flat, include common examples such as rectangles, squares, and triangles. For instance, a rectangle has four sides, and each side is a line segment connecting two vertices.

Key Concepts Related to "Side" in Math:

  1. Polygon:

    • A polygon is a closed shape composed of three or more line segments. Examples include triangles, quadrilaterals, and pentagons.
    • Polygons are often named based on the number of sides they possess. For instance, a triangle has three sides, a quadrilateral has four sides, and a pentagon has five sides.
  2. Regular Polygon:

    • If all the sides of a polygon are equal, it is referred to as a regular polygon.
    • Examples of regular polygons include an equilateral triangle (with three equal sides), a square (with four equal sides), and a regular hexagon (with six equal sides).
  3. Identification and Counting:

    • All two-dimensional shapes have sides, and their names are often determined by the count of these sides.
    • Shapes with three sides are called triangles, those with four sides are quadrilaterals, and so on.
  4. Practice Problems:

    • Engaging in practice problems helps reinforce understanding. For example, identifying the type of polygon based on the given number of sides (e.g., a pentagon has five sides) demonstrates practical application.
  5. Three-Dimensional Figures:

    • While the primary discussion is on two-dimensional shapes, it's worth noting that three-dimensional figures have edges instead of sides. The term "edge" is used to describe the line segments in three-dimensional geometry.
  6. Circle:

    • Unlike polygons, a circle does not have sides. It lacks line segments or points that could be considered as sides. Instead, circles are defined by radii and circumferences.

In summary, understanding the concept of "side" in math is pivotal for comprehending the structure and characteristics of various geometric shapes. From polygons to regular polygons and the distinction between two-dimensional and three-dimensional figures, this knowledge forms the basis for more advanced geometric principles.

What is Side? Definition Facts & Examples (2024)
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