How can we classify different shapes SHAPES Closed

How can we classify different shapes?

SHAPES Closed figures Open figures

CLOSED FIGURES �Closed figures are figures which when drawn starts and ends at the same point. �Some examples are square, circle, rectangle etc.

�Open figures are the figures which when drawn will start and end at different points.

A B

�Perimeter is the length of the boundary around a closed figure.

PERIMETER Hey, can you guys find the perimeter of my land ? � Suppandi’s plot’s perimeter= 11+12+11+12 = 46 c. m

� Let us now find the perimeter of this figure: as, perimeter is the sum of all sides of a shape, Here: perimeter = 4 c. m+8 c. m = 24 c. m

Perimeter Of Rectangle II wonder if there is any easy method to find the perimeter of a rectangle, like of a chess board.

� From this example we can see that perimeter of rectangle is equal to twice the sum of its length and bredth. so, Perimeter of rectangle= length+ bredth+bredth = 2 length+ 2 bredth =2 (l+b)

So finding the perimeter of square will also be easy because we only have to double the length of one side of the square. Isn’t it? Yeah it might be so!!!!! but I am not sure.

� PERIMETER OF SQUARE When length of one side of square= 4 c. m = 4+4+4+4 = 2(4+4) =4 x side SQUARE

PERIMETER OF EQUILATERAL TRIANGLE “Dudes, she does not know how to find the perimeter of an equilateral triangle. I hope you know? ? ? ”

To find the perimeter of an equilateral triangle we just have to add all the 3 sides of it, or as the equilateral triangle have all its sides equal we can multiply the length of side by 3. Perimeter of equilateral triangle = 3 x length of one side. EQUILATERAL TRIANGLE

�Area is the total surface present inside a figure. �Area’s unit is (m 2)

AREA OF A RECTANGLE I wonder what is the formula for finding the area of a rectangle? I will ask Hermione.

Area of a rectangle = length x breadth

� Area of a rectangle = length x breadth � Here if, length of rectangle=4 c. m and if breadth of rectangle=5 c. m then area of rectangle= 4 x 5 = 20 c. m 2 RECTANGLE

Will someone tell me the formula to find the area of a square? I don’t know how to find the area of one side of a dice, which is a square.

�Area of a square = side x side. Here area of square = side x side = 5 c. m x 5 c. m = 25 c. m 2 SQUARE

AREA OF TRIANGLE Do you know how to find the area of a triangle? Such as a side of a pyramid.

AREA OF TRIANGLE � Area of a triangle = 1 breadth x height 2 Here, if breadth = 2 c. m and height = 2 c. m then, area = 1 x 2 2 = 2 c. m 2

� Regular shapes have all its sides of equal length and all its angles of equal magnitude. My garden is a square plot, can I call it as a regular rectangle? Yes, my silly old bear because if a rectangle have all its sides and angles equal then it will become a square.

QUESTIONS Q 1. ) � Ans: So guys can you tell me the area of a triangle with breadth 8 c. m and height 4 c. m? 16 Area of triangle= 1 x 8 x 4 2 = 1 x 32 2 = 16 c. m 2

Q 2. ) Tell me the formula for finding the area of a triangle? Ans: area of a triangle = 1 x breadth x height 2

Find the height of a triangle of area 6 and breadth 2? � Q 3. ) Ans: 6 c. m area of a triangle= 1 x b x h 2 height= area x 2 = 6 x 2 b 2 = 6 c. m

Can you tell me, what is meant by regular shapes? Q 4. ) Ans: Regular shapes have all sides equal and all angles also equal.

� Q 5. ) � Ans: Hey could you tell us the area of a square with one side=12 c. m? Area of square = side x side = 12 x 12 = 144 c. m 2

� Q 6. ) Tell me if I can call a rectangle as a regular square. No, it is not possible. � Ans: No, it is not possible to call a rectangle as a regular square because a regular square will have all its sides and angles equal and it is not a rectangle. But a regular rectangle can be called as a square.

� Q 7. ) Are there figures like regular Hexagon? � Ans: There are figures like regular Hexagon because a hexagon which has all its sides and angles equal are known as a regular shape.

� Q 8. ) Find the perimeter of the following figure? � Ans: Perimeter = 2+5+4+1+4+5+2+5+4+1+4+5 = 42 c. m

� Q 9. ) Can you guys tell me the exact area of a triangle with base 12. 5 c. m and height 10 c. m? � Ans: I know how to do it. Area of triangle = 1 x b x h 2 = 1 x 12. 5 x 10 2 = 125 = 62. 5 c. m 2 2

� Q 10. ) � Ans: Hey can you tell me the number of presents I have if it is the same number as the length of a rectangle with area 26 and breadth 2? Area of rectangle= length x breadth = 26 26= length x 2 length = 26 2 = 13 Santa has 13 presents with him

� All figures can be divided into two as open and closed figure. � Perimeter is the sum of all sides of the boundary of a figure. � Perimeter of rectangle = 2(l+b) � Perimeter of square = 4 x side � Perimeter of equilateral triangle = 3 x side � Area is the amount of surface present inside a figure. � Area of rectangle = length x breadth � Area of square = side x side. � Area of triangle = 1 x b x h 2 Regular shapes have all its sides and angles equal

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