Open Shape – Definition with Examples

What Is an Open Shape?

In geometry, open shapes are defined as shapes or figures with different starting and ending points. In other words, the ends of an open shape do not meet. 

On the other hand, closed shapes are shapes or figures having the same starting and ending points.

Here are some open shape examples:

Examples of open shapes

Open Shapes Around You

Let’s find open shapes in things around us. Here are some examples:

Open shapes in real life

Features of Open Shapes

Look at the given skipping rope. Do the ends of the rope meet?

Skipping rope as open shape

Clearly, the ends don’t meet. This means the starting and the ending point of the rope are different. So, it is an open shape. 

Also, observe that, since their ends do not meet, open shapes do not have a fixed area. 

Let us try something exciting. Let’s drop a bunch of stones over the skipping rope. 

Some stones on skipping rope as open shape

Is stone A lying inside the rope, on it, or outside it? It is lying on the skipping rope. Similarly, stone E is also lying on it. 

Now, stone B is not lying on the rope. So, is it lying inside it or outside it? We cannot say! Since the jumping rope does not have a fixed area, we cannot say whether stone B is lying inside or outside. Similarly, we cannot say whether stones C and D are lying inside or outside the shape.

Therefore, since the ends of an open shape do not meet, it does not have well-defined interior and exterior regions. 

Open And Closed Shapes

Look at the figures below:

Closed and open shape

In figure A, there are no open ends. That is, it has the same starting and ending points. Therefore, it is a closed shape.

On the other hand, starting points and ending points are different in figure B. Therefore, it is an open shape.

Let us note a few more differences:

Difference between open shapes and closed shapes

Let’s Revise

To sum up, there are two types of shapes: open and closed shapes. 

Open shapes are figures or shapes that have different starting and ending points. Their ends are open, i.e., do not meet. 

Since they have open ends, these shapes do not have a fixed area. Also, they do not have a well-defined interior and exterior region. 

Solved Examples

Example 1: Give some examples of open-shaped letters of the English alphabet.

Solution: Some open-shaped letters of the English alphabet are C, M, U, W, N, etc.

Example 2: Is a semicircle an open shape or a closed shape?

Semicircle is an open shape as it has different starting and ending point. 

Open semicircle

3. Which of the following is not an open shape?

3 open shapes and 1 closed shape


Solution: Clearly, shape d does not have any open ends, so it is a closed shape.

Practice Problems

Open Shape - Definition with Examples

Attend this quiz & Test your knowledge.

1Which of the following is not an open-shaped letter of the English alphabet?

L
N
S
O
CorrectIncorrect
Correct answer is: O
The letter “O” is a closed shape as its starting and ending points are the same.

2Which of the following is not a characteristic of an open shape?

It has no well-defined interior.
It has a definite area.
It has different start and end points.
It is different from closed shape.
CorrectIncorrect
Correct answer is: It has a definite area.
Open shape do not have well-defined area because it does not have closed boundary.

3Which of the following is an open shape?

Open Shape – Definition with Examples
A
B
C
D
CorrectIncorrect
Correct answer is: B
Figure b has different starting and ending points. Therefore, it is an open shape.

Frequently Asked Questions

If we join the ends of an open shape, we will get a closed shape.

Yes, line segments is an open shape as it has different starting and ending point.

No, since the ends of an open shape do not meet, they do not have a well-defined boundary. Therefore, open shapes do not have a perimeter.