Common Core Math Vocabulary

# Shape - Definition with Examples

## What is a Shape?

Shape Definition: A shape is a figure or surface area enclosed by a boundary. For example; circle, triangle, rectangle etc.

## Shapes Around Us

The things like clock, money, chessboard, signboard etc. which we come across in everyday life are examples of different shapes.

## Types of Shapes

Geometric shapes are classified according to the number of dimensions they exhibit.

### Two-Dimensional Shapes:

The shapes that exhibit only two dimensions (height and width) are known as 2D shapes or two-dimensional shapes.

### Three-Dimensional Shapes:

The shapes that exhibit three dimensions (height, width and depth) are known as 3D shapes or three-dimensional shapes.

A list of basic geometric shapes along with names and pictures taught to kids in elementary math is given below.

## Open and Closed Shapes

The shapes can be open or closed. They can be formed by curved lines or straight lines.

### Open Shapes:

The shapes that have at least one line segment which is not connected to any other line segment at one of its end point are known as open shapes.

### Closed Shapes:

The shapes that have all its line segments connected at both end points are known as closed shapes.

## Attributes of Geometric Shapes

The attributes of the shapes make them similar or different. Example, a shape with 3 sides is called a triangle whereas a shape with 5 sides is called a pentagon.

The defining attributes do not change for a shape whereas non-defining may change.

## Dimensions of Geometric Shapes

 A point is zero-dimensional as it has no dimension (no length, height or width).
 A line segment/line is one-dimensional as its length is measured only in one direction. A line segment begins with a point.
 Flat figures drawn on a plane whose lengths are measured in two directions (height and width) are called two-dimensional shapes. For example; rectangle, circle, triangle etc. Two-dimensional shapes are formed by combination of line segments and/or curves.
 Solids with three dimensions (height, depth and length) are called three-dimensional figures. For example, cube, cuboid, prism etc. Three-dimensional shapes are formed by combinations of 2D-faces.

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