I can draw and label 2-dimensional figures using angle measures and side lengths.

What you’ll be learning about:

This week, you’ll be learning about 2-D figures, angles, and side measures.

You’ll learn why angles and lengths are important with certain shapes.

You will also learn how to use a protractor.

What you’ll do with what you learn:

You will use a ruler and protractor to identify and make 2-D figures.

You will use angles as tools to create and understand shapes.

VocabularyGet out your vocabulary handout to learn as you watch.

Fill in the blanks as we go.

You will need all of this information for everything you do this week!

Tools:

Protractor A tool used to

measure angles. Always measure

from zero!Ruler

A tool used to measure length.

Always measure from zero!

2 Dimensional (2-D) figures

2-D figures are shapes that can be drawn on flat paper.

2-D figures are made up of angles and sides.

Angles

Angles are the space between two lines, at where they meet.

We mark angles with a semi-circle.

Angles are measured in degrees. Ex: 45°

Acute Angles

Acute angles measure less than 90°.

Think of the A in Acute as a sharp point – acute angles are inside of sharp corners.

Obtuse Angles

Obtuse angles measure greater than 90°.

Think of the O in Obtuse as a dull edge. Obtuse angles are always inside fat corners.

Right Angles

Right angles are exactly 90°.

They are sometimes called square angles.

We mark them with a box.

You will see them when perpendicular lines meet.

Sides & Lines

Some shapes have parallel sides.

Parallel sides are always the same distance apart and will never meet.

Some shapes have perpendicular sides.

Perpendicular sides meet at 90° (right angle).

Polygon Properties

‘Polygon’ is another word for 2-D figure or a shape.Polygons are any shape with 3 or more sides.

There are: Equilateral polygons

Regular polygons

Irregular polygons

Equilateral Polygons

Equilateral polygons are shapes where all sides are the same length. The angles can all be alike, or different.

All sides need to be straight & connected.

Equilateral means “equal lengths”.

Regular Polygons

Regular polygons are equilateral shapes where all angles are the same measure.

A square is a regular polygon, a rhombus is not.

Irregular Polygons

Irregular polygons are shapes with some different angles and side lengths.

Types of Polygons

Now you will learn the names of some basic polygons.

These types of polygons are named for the number of sides they have.

As we go, try using your ruler and protractor to measure the sides and angles of these polygons.

Label what you measure – then decide if they are equilateral, regular, or irregular.

Triangles

Triangles are any 2-D shape that has:

3 sides 3 angles.

Quadrilaterals

Quadrilaterals are shapes with:

4 sides 4 angles

Squares, rectangles, rhombuses, parallelograms, and trapezoids are all quadrilaterals.

Think of the qua in quadrilaterals like the qua in quarters. Quad means 4.

Pentagons

Pentagons have: 5 sides 5 angles

You can find a pentagon inside and around any 5-point star.

The Pentagon building in Washington D.C. is a famous symbol.

Hexagons

Hexagons are shapes with:

6 sides 6 angles

Think of the x to remind you that hexagon means six.

Octagon

Octagons are shapes with:

8 sides 8 angles

Think of an octopus to remind you that octa means eight.