Kerala Syllabus Class 5 Mathematics - Unit 10 Rectangle Math - Questions and Answers | Teaching Manual 

Questions and Answers for Class 5 Mathematics - Unit 10 Rectangle Math - Study Notes | Text Books Solution STD 5 - Maths: Unit 10 Rectangle Math - Questions and Answers | ചതുരകണക്കുകൾ - ചോദ്യോത്തരങ്ങൾ 

അഞ്ചാം ക്ലാസ്സ്‌  Mathematics - Unit 10 Rectangle Math എന്ന പാഠം ആസ്പദമാക്കി തയ്യാറാക്കിയ ചോദ്യോത്തരങ്ങള്‍. ഈ അധ്യായത്തിന്റെ Teachers Handbook, Teaching Manual എന്നിവ ഡൗൺലോഡ് ചെയ്യാനുള്ള ലിങ്ക് ചോദ്യോത്തരങ്ങളുടെ അവസാനം നൽകിയിട്ടുണ്ട്.

STD 5 - Maths: Unit 10 Rectangle Math - Questions and Answers

♦ Textbook Pages: 111, 112
♦ Squares and Rectangles
♦ Some children are making rectangles by joining small squares.
All small squares have sides of  1 centimetre. 
♦ Can you write the width and height of all the rectangles in the picture?
♦ Textbook Page 113
♦ Measuring Boundaries
The children have also pasted coloured threads along the edges of each rectangle they have made.
♦ What is the length of the thread required to paste around the first rectangle?
For the top and bottom of each edge, it is 6 centimetres and 1 centimetre for each of the left and right edges.
Total = 6 + 6 + 1 + 1 = 14 centimetres.
This length, taken around the rectangle, is called its perimeter.
Thus, the perimeter of the rectangle given above is 14 centimetres.
Now we can write the perimeters of the rectangles also in our table:
♦ Textbook Page 114, 115
♦ Measuring Insides
♦ Now, look at the first and the fifth rectangles in our table.
The perimeter of both rectangles is 14 cm. The first is made with 6 small squares. The second rectangle is made with 12 small squares.
That means if  two 14-centimetre-long strings are cut in two different ways to make the edges of  rectangles, the measure of the space inside the rectangles will not be the same:
In other words, the rectangle on the right is more spread out. The measure
of the spread is called area. Just as we measure lengths using fixed lengths such as centimetres and metres, we measure areas using predetermined squares.
The area of a square of sides 1 centimetre is said to be 1 square centimetre.
♦ Now we can add areas also in our table:
The sides of large rectangles (playgrounds, rooms in a building, etc.) are measured in metres. The areas of such rectangles are measured in terms of a square of side 1 metre.
The area of a square of sides 1metre is said to be 1 square metre.
As in the case of small rectangles, two such squares joined together is
said to have area 2 square metres, three of them joined together is said
to have area 3 square metres and so on.
♦ Textbook Page 116
♦ Calculations
Find the perimeter of a rectangle with sides 10 centimetres and 5 centimetres.
Perimeter of the rectangle = (10 + 5) x 2 = 15 x 2 = 30 cm
The perimeter of a rectangle is twice the sum of its sides.
Calculate the perimeters of the rectangles with lengths of sides as below.
(i) 6 centimetres, 3 centimetres
Perimeter = (6 + 3) x 2 = 9 x 2 = 18 cm

(ii) 13 centimetres, 7 centimetres
Perimeter = (13 + 7) x 2 = 20 x 2 = 40 cm

(iii) 6 centimetres, 6 centimetres
Perimeter = (6 + 6) x 2 = 12 x 2 = 24 cm

(iv) 25 metres, 15 metres
Perimeter = (25 + 15) x 2 = 40 x 2 = 80 cm

(v) 34 metres, 16 metres
Perimeter = (34 + 16) x 2 = 50 x 2 = 100 cm

♦ Can you now calculate the area of the rectangle given below?
Draw squares with sides 1 cm inside the rectangle. Similarly, draw 12 squares above it.
Thus area of the rectangle = 6 x 2 = 12 sq.cm
The area of a rectangle is the product of the lengths of its sides.
Note that if the lengths of the sides are in centimetres, the area is in square centimetres, and if the lengths of the sides are in metres, then the area is in square metres.
♦ Textbook Page 116
♦ Now try these problems:
(1) Calculate the areas of  the rectangles with lengths of  sides as below:

(i) 6 centimetres, 3 centimetres 
Area = 6 x 3 = 18 sq.cm

(ii) 12 centimetres, 5 centimetres
Area = 12 x 5 = 60 sq.cm

(iii) 10 centimetres, 10 centimetres 
Area = 10 x 10 = 100 sq.cm

(iv) 8 metres, 5 metres
Area = 8 x 5 = 40 sq.cm

(v) 11 metres, 7 metres
Area = 11 x 7 = 77 sq.cm

(2) Draw rectangles of  area and perimeter as below:
(i) 12 square centimetres, 14 centimetres
Perimeter = 14 cm
Length + height = half of perimeter = 7 cm
Area = 12 sq.cm
Length x height = 12 sq.cm
Length = 4 cm, height = 3 cm
(ii) 12 square centimetres, 16 centimetres
Perimeter = 16 cm
Length + height = half of perimeter = 8 cm
Area = 12 sq.cm
Length x height = 12 sq.cm
Length = 6 cm, height = 2 cm
(iii) 12 square centimetres, 26 centimetres
Perimeter = 26 cm
Length + height = half of perimeter = 13 cm
Area = 12 sq.cm
Length x height = 12 sq.cm
Length = 12 cm, height = 1 cm
(iv) 5 square centimetres, 12 centimetres
Perimeter = 12 cm
Length + height = half of perimeter = 6 cm
Area = 5 sq.cm
Length x height = 5 sq.cm
Length = 5 cm, height = 1 cm
(v) 8 square centimetres, 12 centimetres
Perimeter = 12 cm
Length + height = half of perimeter = 6 cm
Area = 8 sq.cm
Length x height = 8 sq.cm
Length = 4 cm, height = 2 cm
(vi) 9 square centimetres, 12 centimetres
Perimeter = 12 cm
Length + height = half of perimeter = 6 cm
Area = 9 sq.cm
Length x height = 9 sq.cm
Length = 3 cm, height = 3 cm
♦ Textbook Page 123, 124
♦ Some Other Shapes
♦ Now compute the perimeter and area of  each of  the shapes below:
Area = (6 x 1) + (5 x 2) + (4 x 1) 
        = 6 + 10 + 4 = 20 sq.cm
Perimeter = 6 + 4 + 4 + 1 + 2 + 1 + 1 + 1= 20 cm
Area = (5 x 4) - (1 x 1) = 20 - 1 = 19 sq.cm
Perimeter = 5 + 4 + 2 + 1 + 1 + 1 + 2 + 4= 20 cm
Area = (5 x 1) + (4 x 1) = 5 + 4 = 9 sq.cm
Perimeter = 1 + 5 + 1 + 2 + 2 + 4 + 4 + 1= 20 cm
Area = (5 x 1) + (4 x 1) + (3 x 1) + (4 x 1) 
        = 5 + 4 + 3 + 4 = 16 sq.cm
Perimeter = 5 + 5 + 5 + 4 + 4 + 3 + 3 + 1 + 1 + 1 + 1 + 1
                = 15 + 8 + 6 + 5 = 34 cm
Area = (2 x 2) + (6 x 2) + (2 x 2) = 4 + 12 + 4 = 20 sq.cm
Perimeter = 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2
                = 6 + 6 + 6 + 6 = 24 cm

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