Class III - Mathematics by Edu-Primes - Dailymotion

Edu-Primes

Watch the playlist Class III - Mathematics by Edu-Primes on Dailymotion

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00:00Hi kids! Today we will learn various 2D shapes. So let's get started!

00:112D shapes are also called because they have exactly two dimensions.

00:20Length and width or height and width.

00:272D shapes are also called flat shapes.

00:33And kids, do you know what is a polygon?

00:38Polygon is a closed figure which is made up of three or more straight lines.

00:49Like triangle is a polygon with three straight sides.

00:59Square is a polygon with four straight sides.

01:08Now, is circle a polygon?

01:13Circle is a 2D closed figure but is not made up of straight lines.

01:22So it's not a polygon.

01:26Now, let's learn various 2D shapes.

01:32Triangle.

01:35This shape is called triangle or a three-sided polygon.

01:44It has three sides where all can be different or the same.

01:52It has three sides and three edges.

01:58Think of things that are triangle in shape.

02:04These are various things that are triangle in shape.

02:09Now, let's move on to another shape.

02:13This shape is called a circle.

02:16It has no vertex and it just has a boundary which is its single edge.

02:23Think of things that are circle in shape.

02:27These are various things that are circle in shape.

02:33Now, let's learn another shape.

02:37This shape is called an oval.

02:40It too has no vertex.

02:44It just has a boundary which is its single edge.

02:49Think of things that are oval in shape.

02:53These are various things that are oval in shape.

02:57Good.

02:59Now, let's learn another shape.

03:02Semicircle.

03:05This shape is called semicircle.

03:10It is exactly half of a circle.

03:14It has two vertices and two edges.

03:22One straight edge and one curved edge.

03:27So, remember it's not a polygon.

03:32Think of things that are semicircle in shape.

03:36These are various things that are semicircle in shape.

03:43Good.

03:45Now, let's learn another shape.

03:51This is a four-sided shape called square.

03:58Also, four-sided polygon.

04:03All its sides are equal.

04:07It has four vertices and four edges.

04:13Think of things that are square in shape.

04:18These are various things that are square in shape.

04:25Now, we will be learning all shapes that have four sides.

04:31That is, four edges and four vertices.

04:37Rectangle.

04:40This is also a four-sided shape

04:44and is called a rectangle.

04:48Also, a four-sided polygon.

04:53Its opposite sides are equal.

04:58It, too, has four vertices and four edges.

05:04Think of things that are rectangle in shape.

05:11These are various things that are rectangle in shape.

05:17Good.

05:20Now, let's learn another four-sided shape.

05:25This is also a four-sided shape and is called a trapezium.

05:33It is a four-sided shape where one pair of sides is parallel

05:40and the other pair is not parallel.

05:44As here, these sides are parallel to each other

05:50and these two sides are not parallel to each other.

05:56So, this is a trapezium.

06:02It has four sides and four edges.

06:08Think of things that are trapezium in shape.

06:13These are various things that are trapezium in shape.

06:19Good.

06:21Now, let's learn another four-sided shape.

06:28Diamond or rhombus.

06:32This is also a four-sided polygon and is called diamond.

06:40Shape or rhombus shape.

06:44Its opposite sides are equal and parallel to each other

06:51forming two pairs of opposite and equal angles.

06:59One pair of smaller angles, that is acute angles

07:06and one pair of wider angles, that is obtuse angles like this.

07:15These two angles are more than 90 degree or obtuse

07:23and these two angles are less than 90 degree or acute.

07:31It has four sides and four edges.

07:37Think of things that are rhombus in shape.

07:42These are various things that are rhombus in shape.

07:49So, we have learned all the four-sided polygons.

07:54Now, we will learn polygons that have more than four sides.

08:02It is a polygon that has five straight sides

08:07and this is called a pentagon.

08:12It has five vertices and five edges.

08:18And these are some of the pentagon-shaped things.

08:25It is a polygon that has six straight sides

08:31and is called a hexagon.

08:35It has six vertices and six edges.

08:41These are some of the hexagon-shaped things.

08:47Septagon.

08:49It is a polygon that has seven straight sides

08:55and is called a septagon.

08:59It has seven vertices and seven edges.

09:06These are some of the septagon-shaped things.

09:13Octagon.

09:15It is a polygon that has eight straight sides.

09:21It's called a octagon.

09:25It has eight vertices and eight edges.

09:31These are some of the octagon-shaped things.

09:37Nanogon.

09:40It is a polygon that has nine straight sides.

09:45It's called a nanogon.

09:49It has nine vertices and nine edges.

09:55And these are some of the nanogon-shaped things.

10:02Decagon.

10:05It is a polygon that has 10 straight sides

10:11and is called a decagon.

10:15It has 10 vertices and 10 edges.

10:21And these are some of the decagon-shaped things.

10:27So kids, today we learned what are polygons

10:32and various 2D shapes and their basic characteristics.

10:40Now, let's answer a few questions.

10:46John wants to have a window in his room

10:50that has one straight side and one curved side.

10:56Which shape of window does John want?

11:00John wants a semicircle shape of window.

11:04Good!

11:07John wants to cut cardboard in a six-sided shape.

11:12Which of the following shape does John want?

11:16Yeah!

11:18Hexagon shape as it has six straight sides.

11:24Here is a shape cut out from cardboard.

11:28Which of the following shape will fit here?

11:33Yeah!

11:35Pentagon shape will fit here as it has five sides.

11:41Good!

11:44You can go through the video once more

11:48to learn all the shapes by heart.

11:51Now you may go ahead and take a quiz to learn more.

11:55Bye-bye!

2D Shapes - Polygons

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Class III - Mathematics

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