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- Fourth Class Maths
- 2D Shapes and Planes

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Try reviewing these fundamentals first

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Get Started NowStart now and get better maths marks!

Get Started NowStart now and get better maths marks!

Get Started Now- Intro Lesson: a2:06
- Intro Lesson: b9:09
- Intro Lesson: c9:01
- Intro Lesson: d5:12
- Lesson: 1a1:05
- Lesson: 1b1:45
- Lesson: 1c1:14
- Lesson: 2a1:47
- Lesson: 2b2:02
- Lesson: 2c1:46
- Lesson: 2d1:56
- Lesson: 2e2:55
- Lesson: 3a1:30
- Lesson: 3b1:07
- Lesson: 3c2:55
- Lesson: 4a2:27
- Lesson: 4b3:25
- Lesson: 4c4:34

In this lesson, we will learn:

- How to name polygons: triangles, quadrilaterals, pentagons, hexagons, heptagons, and octagons
- How to classify regular vs. irregular polygons
- How to read markings on polygons: hashmarks for congruent sides, semicircles for congruent angles, arrows for parallel sides, and squares (right angles) for perpendicular sides

**Polygons**are 2D shapes with straight**sides**only. All polygons have sides (straight lines/edges) and**vertices**(corners/points where sides meet).- Polygons are named by the
*number of sides*they have:

- Polygons can be
**regular**or**irregular**.**Regular**polygons have**congruent**sides and angles; all sides and all angles are equal.**Irregular**polygons do__not__have same size sides and angles.

**Congruent sides**can be shown with**hashmarks**(matching lines on the sides that are equal)**Congruent angles**can be shown with either**semicircles with hashmarks**, or with**concentric circles**

- IntroductionIntroduction to Classifying Polygons:a)What are polygons?b)Names of different polygons based on number of sides (triangles to octagons)c)Regular or irregular polygons: markings for congruent sides and anglesd)Understanding markings for parallel and perpendicular sides in polygons
- 1.
**Sides and vertices in polygons**

Count the number of sides and vertices in the polygon. Circle the vertices and check mark the sides to help keep track.a)b)c) - 2.
**Classifying polygons by name and regularity**

Look at the picture of the shape and write:- the name of the polygon
- and if it is regular or irregular

a)b)c)d)e) - 3.
**Congruent sides and angles in polygons**

Draw markings for any pairs of equal sides and/or anglesa)b)c) - 4.
**Parallel sides in polygons**

Mark the parallel sides with matching arrows on each pair. How many pairs of sides are parallel?a)b)c)