What are Shapes?
In geometry, a shape can be defined as the form of an object or its outline, outer boundary or outer surface.
Everything we see in the world around us has a shape. We can find different basic shapes such as the two-dimensional square, rectangle, and oval or the three-dimensional rectangular prism, cylinder, and sphere in the objects we see around us. These geometric shapes appear in objects we see as credit cards, bills and coins, finger rings, photo frames, dart boards, huts, windows, magician’s wands, tall buildings, flower pots, toy trains, and balloons.
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Different Types of Shapes
Shapes can be classified into open and closed shapes.
| In geometry, an open shape can be defined as a shape or figure whose line segments and/or curves do not meet. They do not start and end at the same point. | In geometry, a closed shape can be defined as an enclosed shape or figure whose line segments and/or curves are connected or meet. They start and end at the same point. |
Closed geometric shapes can further be put into two broad categories, namely two-dimensional and three-dimensional shapes.
| The 2-Dimensional shape is flat. | A 3-Dimensional Shape is a solid shape. |
| It has two dimensions, that is, length and width. | It has two dimensions, that is, length, width, and depth. |
Here’s a list of 2-D or two-dimensional shapes with their names and pictures:
| Two-Dimensional Geometric Shapes |
Here’s a list of 3-D or three-dimensional shapes with their names and pictures:
| Three-Dimensional Geometric Shapes |
The color, overall size, and orientation called the non-defining attributes of a two-dimensional or three-dimensional shape do not define or affect the shape in any way. These attributes can change without any effect on the shape.
On the other hand, defining attributes such as the number of sides (parallel or non-parallel, straight or curved), vertices, edges, and faces of a shape, whether the shape is open or closed, and the angle measures determine the shape of a two-dimensional or three-dimensional object. Any change in these defining attributes will change the shape.
Solved Examples on Shapes
Example 1: Name the shapes.
- A polygon with 6 sides.
- Outline of a door.
- When you fold square corner to corner.
- A square and a triangle on top of it.
Solution:
- Hexagon
- Rectangle or quadrilateral
- Triangle
- Pentagon
Example 2: Classify the given letters as open shape or closed shape.
C, D, L, M, O, S, U, V, Z
Solution:
Open shape: C, L, M, S, U, V, Z
Closed shape: D, O
Example 3: Identify the solid shape of given objects.
- Globe
- Book
- Cold drink can
- Dice
Solution:
- Sphere
- Cuboid
- Cylinder
- Cube
Example 4: Why is the crescent-shaped moon not a polygon?
Solution:
Crescent shape moon is not a polygon as it has curved lines.
Practice Problems
Shapes
What is 8-sided polygon known as?
A polygon with 8 sides is known as octagon.
How many dimensions does a solid shape have?
All solid shapes are 3-dimensional shapes.
Which of the following statements is incorrect?
Closed shapes are shapes whose start and end points are the same. It is not necessary that it is formed by only straight sides.