NCERT Solutions for Class 6 Maths Chapter 10 Mensuration
Answer :
(a) Perimeter = Sum of all the sides
= 1 + 2 + 4 + 5
= 12 cm
(b) Perimeter = Sum of all the sides
= 23 + 35 + 35 + 40
= 133 cm
(c) Perimeter = Sum of all the sides
= 15 + 15 + 15 + 15
= 60 cm
(d) Perimeter = Sum of all the sides
= 4 + 4 + 4 + 4 + 4
=20 cm
(e) Perimeter = Sum of all the sides
= 1 + 4 + 0.5 + 2.5 + 2.5 + 0.5 + 4
= 15 cm
(f) Perimeter = Sum of all the sides
= 4 + 1 + 3 + 2 + 3 + 4 + 1 + 3 + 2 + 3 + 4 + 1 + 3 + 2 + 3 + 4 + 1 + 3 + 2 + 3
= 52 cm
Q.2 The lid of a rectangular box of sides 40 cm by 10 cm is sealed all around with tape. What is the length of the tape required?
NCERT Solutions for Class 6 Maths Chapter 10 Mensuration
Answer :
Length of required tape = Perimeter of rectangle
= 2 (Length + Breadth)
= 2 (40 + 10)
= 2 × (50) = 100 cm
NCERT Solutions for Class 6 Maths Chapter 10 Mensuration
Answer :
Length of table top = 2 m 25 cm = 2.25 m
Breadth of table top = 1 m 50 cm = 1.50 m
Perimeter of table top = 2 (Length + Breadth)
= 2 (2.25 + 1.50)
= 2 (3.75)
= 2 × 3.75
= 7.5 m
Q.4 What is the length of the wooden strip required to frame a photograph of length and breadth 32 cm and 21 cm respectively?
NCERT Solutions for Class 6 Maths Chapter 10 Mensuration
Answer :
Required length of wooden strip = Perimeter of photograph
= 2 (Length + Breadth)
= 2 (32 + 21)
= 2 (53)
= 2 × 53
= 106 cm
Q.5 A rectangular piece of land measures 0.7 km by 0.5 km. Each side is to be fenced with 4 rows of wires. What is the length of the wire needed?
NCERT Solutions for Class 6 Maths Chapter 10 Mensuration
Answer :
Perimeter of the field = 2 (Length + Breadth)
= 2 (0.7 + 0.5)
= 2 (1.2)
= 2 × 1.2
= 2.4 km
Q.6 Find the perimeter of each of the following shapes:
(a) A triangle of sides 3 cm, 4 cm and 5 cm
(b) An equilateral triangle of side 9 cm
(c) An isosceles triangle with equal sides 8 cm each and third side 6 cm.
NCERT Solutions for Class 6 Maths Chapter 10 Mensuration
Answer :
(a) Perimeter of triangle = 3 + 4 + 5
= 12 cm
(b) Perimeter of an equilateral triangle = 3 × side
= 3 × 9
= 27 cm
(c) Perimeter of isosceles triangle = 8 + 8 + 6
= 22 cm
Q.11 A piece of strings is 30 cm long. What will be the length of each side if the string is used to form:
(a) a square?
(b) an equilateral triangle?
(c) a regular hexagon?
NCERT Solutions for Class 6 Maths Chapter 10 Mensuration
Answer :
(a) Perimeter of square = 30 cm
4 × side = 30
Side = \(\frac{30}{4} \)
Side = 7.5 cm
(b) Perimeter of an equilateral triangle = 30 cm
3 × side = 30
Side = \(\frac{30}{10} \)
Side = 10 cm
(c) Perimeter of a regular hexagon = 30 cm
6 × side = 30
Side = \(\frac{30}{6} \)
Side = 5 cm
NCERT Solutions for Class 6 Maths Chapter 10 Mensuration
Answer :
Side of square = 250 m
Perimeter of square = 4 × side
= 4 × 250
= 1000 m
Cost of fencing = Rs 20 per m
Cost of fencing for 1000 m = Rs 20 × 1000
= Rs 20,000
Q.14 Find the cost of fencing a rectangular park of length 175 cm and breadth 125 m at the rate of ? 12 per metre.
NCERT Solutions for Class 6 Maths Chapter 10 Mensuration
Answer :
Length = 175 cm
Breadth = 125 m
Perimeter of rectangular park = 2 (Length + Breadth)
= 2 (175 + 125)
= 2 × (300)
= 2 × 300
= 600 m
Cost of fencing = 12 × 600 = Rs 7200
Q.15 Sweety runs around a square park of side 75 m. Bulbul runs around a rectangular park with length 60 m and breadth 45 m. Who covers less distance?
NCERT Solutions for Class 6 Maths Chapter 10 Mensuration
Answer :
Perimeter of square = 4 × side
= 4 × 75
= 300 m
\(\therefore \)Distance covered by Sweety is 300 m
Perimeter of rectangular park = 2 (Length + Breadth)
= 2 (60 + 45)
= 2 × 105
= 210 m
Hence, Bulbul covers less distance than Sweety.
Q.16 What is the perimeter of each of the each of the following figures? What do you infer from the the answers?
NCERT Solutions for Class 6 Maths Chapter 10 Mensuration
Answer :
(a) Perimeter of square = 4 × side
= 4 × 25
= 100 cm
(b) Perimeter of rectangle = 2 (40 + 10)
= 2 × 50
= 100 cm
(c) Perimeter of rectangle = 2 (Length + Breadth)
= 2 (30 + 20)
= 2 (50)
= 2 × 50
= 100 cm
(d) Perimeter of triangle = 30 + 30 + 40
= 100 cm
All the figures have same perimeter.
Q.17 Avneet buys 9 square paving slabs, each with a side of 1 / 2 m. He lays them in the form of a square.
(a) What is the perimeter of his arrangement [fig 10.7(i)]?
(b) Shari does not like his arrangement. She gets him to lay them out like a cross. What is the perimeter of her arrangement [(Fig 10.7 (ii)]?
(c) Which has greater perimeter?
(d) Avneet wonders if there is a way of getting an even greater perimeter. Can you find a way of doing this? (The paving slabs must meet along complete edges i.e they cannot be broken.)
NCERT Solutions for Class 6 Maths Chapter 10 Mensuration
Answer :
(a) Side of square = 3 × side
= 3 × \(\frac{1}{2} \)
= 3 / 2 m
Perimeter of Square = 4 × \(\frac{3}{2} \)
= 2 × 3
= 6 m
(b) Perimeter = 0.5 + 1 + 1 + 0.5 + 1 + 1 + 0.5 + 1 + 1 + 0.5 + 1 + 1
= 10 m
(c) The arrangement in the form of cross has greater perimeter
(d) Perimeters greater than 10 m cannot be determined.
NCERT Solutions for Class 6 Maths Chapter 10 Mensuration
Answer :
(a) Number of full squares = 9
Area of 1 square = 1 sq unit
\(\therefore \)Area of 9 squares = 9 x 1 sq unit
= 9 sq units.
So, the area of the portion covered by 9 squares = 9 sq units
(b) Number of full squares = 5
\(\therefore \) Area of the figure = 5 x 1 sq unit = 5 sq units
(c) Number of full squares = 2
Number of half squares = 4
\(\therefore \) Area of the covered figure
= 2 x 1 + 4 x \(\frac{1}{2} \) = 2 + 2 = 4 sq units
(d) Number of full squares = 8
\(\therefore \) Area of the covered portion of the figure
= 8 x 1 sq unit = 8 sq units.
(e) Number of full squares = 10
Area covered by the figure = 10 x 1 sq unit = 10 sq units.
(f) Number of full squares = 2
Number of half squares = 4
\(\therefore \) Area of the covered figure
= (2 x 1 + 4 x \(\frac{1}{2} \))= (2 + 2) sq units = 4 sq units.
(g) Number of full squares = 4
Number of half squares = 4
\(\therefore \) Area of the covered figure = (4 x 1 + 4 x 12)
= (4 + 2) sq units = 6 sq units.
(h) Number of full squares = 5
\(\therefore \) Area of the covered figure
= 5 x 1 sq unit = 5 sq units.
(i) Number of full squares = 9
\(\therefore \) Area of the covered figure
= 9 x 1 sq units = 9 sq units.
(j) Number of full squares = 2
Number of half squares = 4
\(\therefore \) Area of the covered figure
=(2 x 1 + 4 x \(\frac{1}{2} \)) sq units
= (2 + 2) sq units = 4 sq units.
(k) Number of full squares = 4
Number of half squares = 2
\(\therefore \) Area of the covered figure
= (4 x 1 + 2 x \(\frac{1}{2} \))sq units
= (4 + 1)sq units = 5sq units
(l) Number of full squares = 4
Number of squares more than half = 3
Number of half squares = 2
\(\therefore \) Area of the covered figure
= (4 x 1 + 3 x 1 + 2 x \(\frac{1}{2} \) sq units
= (4 + 3 + 1) sq units = 8 sq units.
(m) Number of full squares = 6
Number of more than half squares = 8
Area of the covered figure = (6 x 1 + 8 x 1) sq units
= (6 + 8) sq units = 14 sq units.
(n) Number of full squares = 9
Number of more than half squares = 9
\(\therefore \) Area of the covered figure
= (9 x 1 + 9 x 1) sq units = (9 + 9) sq units = 18 sq units.
Q.1 Find the area of the rectangles whose sides are:
(a) 3 cm and 4 cm
(b) 12 m and 21 m
(c) 2 km and 3 km
(d) 2 m and 70 cm
NCERT Solutions for Class 6 Maths Chapter 10 Mensuration
Answer :
Area of rectangle = Length × Breadth
(a) l = 3 cm and b = 4 cm
Area = l × b = 3 × 4 = 12 \( cm^2 \)
(b) l = 12 m and b = 21 m
Area = l × b = 12 × 21
= 252 \( m^2 \)
(c) l = 2 km and b = 3 km
Area = l × b = 2 × 3
= 6 \( km^2 \)
(d) l = 2 m and b = 70 cm = 0.70 m
Area = l × b = 2 × 0.70
= 1.40 \( m^2 \)
NCERT Solutions for Class 6 Maths Chapter 10 Mensuration
Answer :
(a) Area of square = \( side^2 \)
= \( 10^2 = 100 cm^2 \)
(b) Area of square =\( side^2 \)
(c) Area of square = \(side^2 \)
\( = 5^2 = 25 cm^2 \)
Q.3 The length and breadth of three rectangles are as given below:
(a) 9 m and 6 m
(b) 17 m and 3 m
(c) 4 m and 14 m
Which one has the largest area and which one has the smallest?
NCERT Solutions for Class 6 Maths Chapter 10 Mensuration
Answer :
(a) Area of rectangle = l × b
\(= 9 × 6 = 54 m^2 \)
(b) Area of rectangle = l × b
\( = 17 × 3 = 51 m^2 \)
(c) Area of rectangle = l × b
\( = 4 × 14 = 56 m^2 \)
Area of rectangle 56 \( m^2 \) i.e (c) is the largest area and area of rectangle 51 \( m^2 \) i.e (b) is the smallest area
Q.5 What is the cost of tiling a rectangular plot of land 500 m long and 200 m wide at the rate of Rs 8 per hundred sq m.?
NCERT Solutions for Class 6 Maths Chapter 10 Mensuration
Answer :
Area of land = length × breadth
\( = 500 × 200 = 1,00,000 m^2 \)
Cost of tiling 1,00,000 sq m of land = (8 × 1,00,000) / 100
= Rs 8000
Q.8 A floor is 5 m long and 4 m wide. A square carpet of sides 3 m is laid on the floor. Find the area of the floor that is not carpeted.
NCERT Solutions for Class 6 Maths Chapter 10 Mensuration
Answer :
Area of floor = l × b = 5 × 4
\(= 20 m^2 \)
Area of square carpet = 3 × 3
\(= 9 m^2 \)
Area of floor that is not carpeted = 20 – 9
\(= 11 m^2 \)
Q.9 Five square flower beds each of sides 1 m are dug on a piece of land 5 m long and 4 m wide. What is the area of the remaining part of the land?
NCERT Solutions for Class 6 Maths Chapter 10 Mensuration
Answer :
Area of flower square bed = 1 × 1
\(= 1 m^2 \)
Area of 5 square bed = 1 × 5
\(= 5 m^2 \)
Area of land = 5 × 4
\(= 20 m^2 \)
Remaining part of the land = Area of land – Area of 5 square bed
\(= 20 – 5 = 15 m^2 \)
Q.10 By splitting the following figures into rectangles, find their areas (The measures are given in centimetres).
NCERT Solutions for Class 6 Maths Chapter 10 Mensuration
Answer :
(a) Area of HKLM = 3 x 3 =\( 9 cm^2\)
Area of IJGH = 1 x 2 = 2 \(cm^2\)
Area of FEDG = 3 x 3 = 9 \(cm^2\)
Area of ABCD = 2 x 4 = 8 \(cm^2\)
Total area of the figure = 9 + 2 + 9 + 8 = 28 \(cm^2\)
(b) Area of ABCD = 3 x 1 = 3 \(cm^2\)
Area of BDEF = 3 x 1 = 3 \(cm^2\)
Area of FGHI = 3 x 1 = 3 \(cm^2\)
Total area of the figure = 3 + 3 + 3 = 9 \(cm^2\)
Q.11 Split the following shapes into rectangles and find their areas. (The measures are given in centimetres)
NCERT Solutions for Class 6 Maths Chapter 10 Mensuration
Answer :
(a) Area of rectangle ABCD = 2 x 10 = 20 \(cm^2 \)
Area of rectangle DEFG = 10 x 2 = 20 \(cm^2 \)
Total area of the figure = 20 + 20 = 40 \(cm^2 \)
(b) There are 5 squares each of side 7 cm.
Area of one square = 7 x 7 = 49\(cm^2 \)
Area of 5 squares = 49 x 5 = 245 \(cm^2 \)
(c) Area of rectangle ABCD = 5 x 1 = 5 \(cm^2 \)
Area of rectangle EFGH = 4 x 1 = 4 \(cm^2 \)
Total area of the figure = 5 + 4 \(cm^2 \)
Q.12 How many tiles whose length and breadth are 12 cm and 5 cm, respectively will be needed to fit in a rectangular region whose length and breadth are respectively?
(a) 100 cm and 144 cm
(b) 70 cm and 36 cm
NCERT Solutions for Class 6 Maths Chapter 10 Mensuration
Answer :
(a) Area of rectangle = 100 × 144
= 14400 cm
Area of one tile = 5 × 12
\(= 60 cm^2 \)
Number of tiles = \(\frac{(Area of rectangle)}{(Area of one tile)} \)
\(= \frac{14400}{60} \) = 240
Hence, 240 tiles are needed
(b) Area of rectangle = 70 × 36
\(= 2520 cm^2 \)
Area of one tile = 5 × 12
\(= 60 cm^2 \)
Number of tiles = \(\frac{(Area of rectangle)}{(Area of one tile)} \)
=\(\frac{2520}{60} = 42 \)