What are Quadrilaterals?
Basics on the topic What are Quadrilaterals?
Quadrilaterals – Definition
What are quadrilaterals? A quadrilateral is a special flat, four sided shape. A quadrilateral is also a polygon. The ‘quad’ part of the quadrilateral meaning refers to the number four. So, how many sides does a quadrilateral have? It has four.
Quadrilaterals – Properties
In order for a shape to meet the definition of quadrilateral, it must have the four properties of a quadrilateral:
 It must have four straight sides,
 Four corners,
 Be fully closed,
 And be twodimensional, or flat.
These are called defining quadrilateral attributes and can never change. They are characteristics that have to stay the same.
However, some quadrilateral characteristics can change and the shape can still be called a quadrilateral.These characteristics are called nondefining attributes. So, quadrilateral polygons can be any color, size, or face in any direction.
Identifying Quadrilaterals
What does a quadrilateral look like? A quadrilateral can look like many things. Let’s use an example to see if we can spot what one looks like. Is this a picture of a quadrilateral?
First, we need to determine if this shape has all four defining attributes of a quadrilateral. It has four straight sides. It has four corners. It is closed and it's twodimensional. This shape is a quadrilateral because it meets all four defining attributes
Quadrilaterals – Summary
Remember, the definition of a quadrilateral is a shape that must meet these requirements:
#  Requirements 

1  It must have four straight sides. 
2  It must have four corners. 
3  It must be fully closed. 
4  It must be twodimensional or flat. 
However, the size, color, and direction of a quadrilateral can change.
Have you practiced with pictures of quadrilateral shapes yet? On this website, you can also find examples of quadrilateral shapes, quadrilateral worksheets, and interactive exercises for 2nd grade.
Transcript What are Quadrilaterals?
Nico and Nia bought glowinthedark shapes to stick to the attic ceiling! They can't wait to put them up, but first they must read the directions. The directions say to put extra sticky tack on the quadrilaterals, but Nia and Nico don't know what a quadrilateral is! Let's help them by learning about "Quadrilaterals"! Quadrilaterals are special flat, four sided shapes. The ‘quad’ part of the word, quadrilateral, means four. In order for a shape to be called a quadrilateral, four things must always be true: It must have four straight sides, four corners, be fully closed, and be twodimensional, or flat. These are called defining attributes and can never change, if a shape is to be called a quadrilateral. They are characteristics that have to stay the same. However, some characteristics can change and the shape can still be called a quadrilateral. These characteristics are called nondefining attributes. So, quadrilaterals can be any color, size, or face any direction. Let's use this checklist to see which glow in the dark quadrilaterals we need to put the extra sticky tac on. First, we need to determine if this shape has all four defining attributes of a quadrilateral. It has four straight sides. It has four corners. It is closed and it's two dimensional. This shape IS a quadrilateral because it meets all four defining attributes. Let's put extra sticky tac on it. Take a look at this shape: does it have all four defining attributes of a quadrilateral? It does not have four straight sides, it has ten. This shape does not have four sides so we can stop checking since it can't meet all the requirements. This shape does not need extra sticky tack. Let's look at THIS shape now. Does it meet all four defining attributes of a quadrilateral? It has four straight sides. It has four corners. It is closed and it's two dimensional. This shape IS a quadrilateral because it meets all four of the defining attributes. Let's put extra sticky tack on it. Now, try this shape on your own. Use the checklist to see if the shape meets all four defining attributes. Is this shape a quadrilateral? This shape is not a quadrilateral. While it is closed and its sides are straight, it has more than four sides and more than four corners. It's also not flat, it's three dimensional! So this shape does not get extra sticky tack. While Nico and Nia continue to sort through the other shapes, let's review. Today we learned about quadrilaterals. In order for a shape to be called a quadrilateral, it must have these four defining attributes: four straight sides, four corners, be fully closed and be twodimensional. However, the size, color, and direction of a quadrilateral can change. "That's the last one Nico, can you hit the lights?" "I think I want to make a wish!"
What are Quadrilaterals? exercise

What are the defining attributes of a quadrilateral?
HintsRemember, if a shape has more than 4 sides, it can't be a quadrilateral.
Remember if a shape is 3D and not flat, it can't be a quadrilateral.
Solution First, check if the figure has 4 straight sides.
 Next, check for 4 corners.
 Then, see if the figure is closed with no open areas.
 Finally, see if the figure is flat and not 3D.

Which of the following is a quadrilateral?
Hints How many sides does the figure have?
 Are the sides straight?
How many corners does the figure have?
Is the figure closed or are there any open sides?
Is the figure 2D or 3D?
SolutionEvery quadrilateral must:
 Have 4 straight sides
 Have 4 corners
 Be closed
 Be 2D (flat)
If one of these is not true, then it is not a quadrilateral.

Which of the following is NOT an attribute of a quadrilateral?
HintsYou are looking for the answer that is NOT a characteristic of quadrilaterals.
This is a quadrilateral.
This is not a quadrilateral.
This is an example of a 3D, or solid, shape.
SolutionQuadrilaterals have:
 4 straight sides
 4 corners
 are closed
 are 2D or flat

Determine which shapes are quadrilaterals.
HintsFirst check how many sides a figure has to determine if it is a quadrilateral.
Next check if it is 2D or 3D to determine if it is a quadrilateral.
SolutionQuadrilaterals:
 4 straight sides
 4 corners
 closed
 2D or flat

Determine if the shapes are quadrilaterals or not.
HintsHow many sides does the shape have?
Are those sides straight or curved?
This is an example of a quadrilateral.
SolutionQuadrilaterals:
 4 straight sides
 4 corners
 closed
 2D or flat
 More than 4 sides
 More than 4 corners or no corners
 Open
 Are 3D

Name the quadrilaterals.
HintsA square has 4 sides of equal length.
A rectangle has 4 right corners.
A quadrilateral must be a closed 2D shape with 4 corners and 4 sides.
SolutionA quadrilateral must be a closed 2D shape with 4 corners and 4 sides. The picture shows the shapes matched with the names.