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Classify quadrilaterals, including rectangles, rhombuses, and squares.

A quadrilateral is a polygon with four sides.

### Study some examples

Here are some examples of quadrilaterals:

### Try it yourself

Which of the following shapes are quadrilaterals?

Some quadrilaterals go by special names like rectangle, rhombus, and square. Let's learn about them!

## Rectangles

What makes a shape a rectangle?
• There are four right angles.
• There are four sides because it's a quadrilateral.

### Study some examples

Here are some examples of rectangles:

### Try it yourself

Which of the following shapes are rectangles?

### Challenge problem

Let's consider one more shape:

Does the shape have four right angles?

So, is the shape a rectangle?

## Rhombuses

What makes a shape a rhombus?
• All sides are the same length.
• There are four sides because it is a quadrilateral.

### Study some examples

Here are some examples of rhombuses:

### Try it yourself

Which of the following shapes are rhombuses?

## Squares

What makes a shape a square?
• All sides are of equal length.
• There are four right angles.
• There are four sides because it's a quadrilateral.

### Study some examples

Here are some examples of squares:

### Try it yourself

Which of the following shapes are squares?