In geometry, **shapes** define the outline or the boundary of an object. A shape is defined for an object or any external surface or boundary, apart from other properties such as colour or material type. For example, a blue ball, made up of rubber materials is round in shape. In the same way, there are various geometric shapes we see in our day-to-day life. In this article, we are going to discuss what shapes are? different types of shapes in Maths, and the shapes for kids, and the list of two-dimensional shapes and three dim shapes in detail with examples.

## What are Shapes?

In Mathematics, shapes define the outline or the boundary of an object. The shapes can be classified into different types based on their properties. In general, the shapes are closed by an outline or boundary, which is made up of points, lines and curves, and so on.

## Types of Shapes

Based on the dimension of the shapes, each shape can be classified as follows:

**Two-dimensional shapes (2D shapes)**: As the name suggests, it has only two dimensions such as length and breadth. The names of basic 2d shapes are circle, triangle, square, rectangle, and so on.

**Three-dimensional Shapes (3D shapes):** Also known as solids have three dimensions, such as length, breadth, and height. The basic 3d shapes are sphere, cube, cone, cylinder, etc.

Some of the real-life examples of shapes are a rectangular plot, a circular ground, a sugar cube, a gas cylinder, an ice cream cone, etc.

It is not necessary that shapes have to be regular like circles, squares, cubes, cylinders, etc. Shapes are also classified as regular or irregular and concave or convex. Regular shapes have uniform sizes. It means their dimensions are uniformly distributed. For example, a regular pentagon. But irregular shapes are not uniformly distributed in the XY plane. Also, there is a huge category of simple shapes. For example, a polygon, which is a closed shape, can be categorized into different figures based on the number of sides. A polygon is made up of line segments that are joined together end to end.

### Polygons – Based on Sides

The types of the polygon are:

- Triangles (3-sided polygon)
- Quadrilaterals (4-sided polygon)
- Pentagon (5-sided polygon)
- Hexagon (6-sided polygon)
- Heptagon (7-sided polygon)
- Octagon (8-sided polygon)
- Nonagon (9-sided polygon)
- Decagon (10-sided polygon)

### Polygons – Based on Regularity

- A regular polygon has all its sides equal in length and all its angles equal in measure.
- An irregular polygon does not have all the sides equal in length and angles are also not equal in measure.

### Concave and Convex Polygon

- A convex polygon has all its interior angles less than 180 degrees. The diagonals of a convex polygon lie within the polygon.
- A concave polygon has at least one of its interior angles to be more than 180 degrees. Also, not all the diagonals of the concave polygon lie within the shape.

## List of 2D shapes

Triangle is a polygon with the least number of sides and is also classified into six categories based on sides and angles. The names of different triangles are:

- Scalene triangle (All sides are unequal in length)
- Isosceles triangle (Any two sides are equal in length)
- Equilateral triangle (All the three sides are equal in length)
- Acute-angled triangle (All the three interior angles are less than 90 degrees)
- Obtuse-angled triangle (Any one of the three interior angles is more than 90 degrees)
- Right-angled triangle (Any one of the three interior angles is exactly equal to 90 degrees)

### Types of Quadrilaterals

A quadrilateral is a four-sided, two-dimensional, closed shape. It is also called a four-sided polygon. It is categorized into different categories, such as:

- Square (All four sides are equal and all interior angles are equal to 90 degrees)
- Rectangle (Opposite sides are equal and parallel to each other, interior angles are equal to 90 degrees)
- Parallelogram (Opposite sides are equal and parallel)
- Rhombus (All sides are equal and diagonals bisect at 90 degrees)
- Kite (Adjacent sides are equal and diagonals intersect at 90 degrees)
- Trapezium (Only one pair of opposite sides are parallel)

## List of 3D shapes

Above, we have discussed all the two-dimensional shapes. Here we will see the 3d shapes mentioned in geometry.

Three-dimensional shapes are determined by three major axes, i.e., x-axis, y-axis and z-axis. These are also called solids since they appear as solid structures. The common solids that are seen in everyday lives are:

- Sphere (A round shape)
- Cube (has 6 faces, 8 vertices, 12 edges and faces are in square shape)
- Cuboid (has 6 faces, 8 vertices, 12 edges and faces are in a rectangular shape)
- Cone (1 circular base, 1 vertex and a curved surface)
- Cylinder (two parallel circular bases and a curved surface)

**Also check: **

## Shapes for Kids

In primary classes, kids are taught basic and advanced shapes.

**Basic Shapes for Kids**

Kids are first introduced to shapes like squares, triangles, circles, and rectangles. After a kid has mastered the categorization and naming of these shapes, they are introduced to more complicated shapes. A lot of time is spent on basic shapes for kids. This is due to the fact that all of the shapes are taught at a later level based on the concepts learned while learning fundamental shapes for children.

**Advanced Shapes for Kids**

Once a kid has mastered fundamental shapes, he or she is ready to move on to more advanced shapes for kids. Arrows, stars, hearts, and other forms are examples of these. In preschool, advanced shapes do not incorporate 3-D shapes because it may cause confusion. Kids that have a good understanding of basic shapes will ace the subject.

Teachers can teach children different shapes, using examples of objects which we see in classrooms and homes. Some of the examples are given here:

- Square-shaped tiles in the classroom
- The clock at the house is circular or round in shape
- The rooftop of the house is triangular
- Heart-shaped biscuits
- Star-shaped mirror

## Frequently Asked Questions on Shapes

### What are shapes?

In geometry, shapes are defined as the form or outline of an object that determines its properties.

### What are 2d shapes and 3d shapes?

Two-dimensional shapes are flat shapes that are defined in the XY plane. Three-dimensional shapes are solids that have thickness extended on the z-axis.

### What are the different types of shapes?

The different types of shapes are 2d and 3d shapes, regular and irregular shapes, concave and convex shapes, and closed and open shapes.

### What are the basic 16 types of shapes?

The basic shapes are circle, square, rectangle, parallelogram, rhombus, kite, scalene triangle, isosceles triangle, equilateral triangle, acute triangle, obtuse triangle, right triangle, trapezoid, pentagon, and hexagon.

### What are the basic 3d solids?

The basic 3d shapes are sphere, cube, cone, cuboid and cylinder.

### What are regular and irregular shapes?

A regular shape is uniform and has sides and angles equal. The irregular shape is non-uniform and has unequal sides and angles.