2D Shapes - Polygons
Transcript
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!