5th Grade Math

2D Figures

Unit 5


2D Figures

Classifying Figures

What are 2D shapes? 2D shapes have sides and corners, and are completely flat. Watch the video to learn all about 2D shapes, like circles, triangles, squares, rectangles, pentagons, hexagons and octagons!

There are certain characteristics that all shapes in a category have in common. For example, all rectangles have four right angles and squares are rectangles, so all squares have four right angles. Let's look at the properties of other 2D shapes! Below is a diagram of quadrilaterals and their properties! Quadrilateral means any shape with 4 sides (note: quad means 4 so a quadrilateral has 4 sides)!

Polygon

Polygon is the largest category, and all of the shapes that we will study today fall into the category of a polygon.

Parallelogram

A parallelogram is a sub-category within a quadrilateral. The definition of a parallelogram is a quadrilateral with both pairs of opposite sides parallel. Here are some more properties of parallelograms:

  1. It has 2 sets of opposite congruent sides (meaning opposite sides are equal in shape and size)

  2. It has 2 sets of opposite congruent angles (meaning opposite angles are equal in shape and size)

  3. Diagonals bisect each other.

Watch this super helpful video on how to classify figures and creating a hierarchy (which we will practice below)!

Practice classifying various two dimensional shapes into groups and subgroups!

We can also use diagrams to order different 2D shapes!

Let's create a hierarchy diagram using the list of words given below:

There are many ways to create a hierarchy diagram, so don't worry if yours doesn't look like the one that is shown!

Here is our list of words!

Here is another list of words!

Here is our hierarchy diagram! You see that quadrilaterals are a sub-category of polygons, so the belong under the polygon. Next, rectangles and rhombi are examples of quadrilaterals, which is why there is are arrow pointing away from the Quadrilaterals and towards the Rectangles and Rhombi. Finally, a square is both a rectangle and a rhombi, so both arrows point toward the Square.

This is another example of a hierarchy diagram! Notice how each box is inside another one? This means that it belongs within the bigger box. For example, parallelogram is inside the quadrilateral box, that means a parallelogram is an example of a quadrilateral!