Open Shapes - Definition, Facts & Visual Examples
Shivam Singh13 Nov, 2025
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What is an Open Shape?
An open shape is a shape where the start and end points do not meet. That means the figure is not fully closed. It can be made of straight lines, curved lines, or both, but at least one end is left open. For example, if you draw a “V” or a “C” on paper, you will see that the lines do not connect fully. These are open shape examples.
What Are Open Geometric Shapes?
Open geometric shapes are shapes in geometry that are not fully joined. They are made of lines or curves that don’t meet at one point. These shapes don’t form a complete boundary, so they don’t have a fixed area or space inside.
Some common open geometric shapes are:
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A single line
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A bent wire
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A shape like “<” or “(”
Since the ends don’t meet, open geometric shapes cannot trap space like a triangle or square can.
Read More: 3D Shapes in Maths
Features of Open Shapes
Let’s look at the main features of open shapes:
Open Shapes Do Not Connect at the Ends
The most important feature of an open shape is that its start and end points do not meet. This means the shape has a gap. For example, the letter “C” is not closed at the ends, so it is an open shape. This is different from a closed shape like a circle, where all the sides or curves join back together.
Open Shapes Have No Fixed Area
Since open geometric shapes don’t close, they cannot trap space inside. That’s why they do not have a measurable area. A square or triangle has a clear area because it is closed, but an open shape like a line or hook does not.
Open Shapes Don’t Have a Clear Inside or Outside
Because the shape doesn’t form a complete loop, there’s no clear “inside” or “outside.” For example, if you draw an open curve like the letter “U”, you cannot say for sure which part is inside the shape.
Open Shapes Can Be Made with Lines or Curves
Open shapes can be created using straight lines, curved lines, or a mix of both. Whether it’s a zigzag line, a wave, or part of a circle, all of these can form open geometric shapes as long as the ends don’t meet. A curve that stays open is called an open curve shape.
Read More: Difference Between 2D and 3D Shapes
Open and Closed Shapes Difference
Open and closed shapes have different features based on whether their ends meet. Here is the table showing their differences:
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Open and Closed Shape Differences |
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Features |
Open Shape |
Closed Shape |
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Ends |
The lines or curves do not meet at the ends, so the shape stays open. |
The lines or curves join at the ends to form a complete shape. |
|
Area |
An open shape cannot trap space, so it has no measurable area. |
A closed shape holds space inside and has a fixed area. |
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Inside/Outside |
It is difficult to say what is inside or outside an open shape. |
The shape has a clearly defined inside and outside region. |
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Shape type |
Open shapes are incomplete or broken, with at least one open end. |
Closed shapes are complete figures that make a full loop. |
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Alphabet Example |
Letters like “U”, “C”, and “V” are common open shape examples. |
Letters like “O”, “D”, and a circle are closed shapes. |
Read More: Area of Shapes
What Is an Open Curve Shape?
An open curve shape is a type of open shape that is made using curves instead of straight lines. It bends, but the curve does not loop back to the starting point.
For example, if you draw the letter “C”, that is an open curve shape. It has a curved line, but the ends are open. Other open curve shapes include parts of circles, wave-like lines, or hooks.
Open Shape Examples in Real Life
Here are some common open shape examples you may see in your everyday life:
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The letter “L”, “C”, or “V”
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A rope laid on the floor in a wavy pattern
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An incomplete triangle
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A line drawn with one end left open
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A part of a circle (semi-curve)
All these are open shape examples because their lines or curves do not fully connect.
Open Shape Solved Examples
Example 1: Identify whether the letter “C” is an open or closed shape. Explain why.
Solution: The letter “C” is an open curve shape because it is made of a curved line and its ends do not join together. It does not enclose any space. So, “C” is an open shape.
Example 2: A student draws a shape using two lines that meet at one point but leave the other ends open. Is this an open shape?
Solution: Yes, the shape is an open shape because the two lines do not form a closed loop. The ends are not joined, and there is a gap in the figure. This is a basic example of open geometric shapes.
Example 3: Compare a circle and the letter “U”. Which one is an open shape and why?
Solution: A circle is a closed shape because it forms a full loop without gaps. The letter “U” is an open shape because its ends do not meet. “U” is also an open curve shape since it is curved and not closed.
Also read: Geometry
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