# Classifying two-dimensional figures

## Overview

Many **two-dimensional** objects can be categorized as more than one shape. For example, is the image below a square or rectangle?

At first, we may say the image is a square. However, it is also a rectangle. Take a look at the chart below.

The chart shows how shapes can be organized into hierarchies based on their attributes.

By looking at the chart, we can see that a square is also a rectangle.

This is because a rectangle is a shape with four straight sides and four right angles.

A square has both of those attributes.

### Is a rectangle a square?

By looking at the chart, we can see that a rectangle is a parallelogram, but not always a square.

To be a square, the sides of the shape must have equal lengths.

A rectangle does not need to have equal sides.

### How do I organize shapes into a hierarchy?

In order to organize shapes into a hierarchy, you need to consider their attributes or properties. Let’s practice!

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A square is ___________ a rectangle. Explain your answer.

- Always
- Sometimes
- Never

Always

A square is a special kind of rectangle. It has four sides with equal angles

A rhombus is __________________ a square. Explain your answer.

- Always
- Sometimes
- Never

Sometimes

A square can be a rhombus, but not all rhombuses are squares.

A parallelogram is ___________________ a rectangle. Explain your answer.

- Always
- Sometimes
- Never

Sometimes

A rectangle can be a parallelogram, but not all parallelograms are rectangles.

Which two shapes are **not** squares? Select and explain your answer.

Shape 2 and 3.

Which shape is **not** parallelograms? Select and explain your answer.

Shape 3.

Two of its sides are not parallel.

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