Ncert Solutions For Class 7 Maths Ex 11.1

Ncert Solutions For Class 7 Maths Chapter 11 Ex 11.1

 

Q1. Find

                (a) the area of the land

                (b) the price of the land,

                If the land is of rectangular shape measuring 300 m in length and 400 m in breadth.  The cost of 1m2 land is Rs. 10000.

Ans:       (a) Area = Length (l) x Breadth (b)

= 300 x 400

= 120000 m2

(b) Cost of 1 m2 land = Rs 10000

Cost of 120000 m2 land = 10000 x 120000 = Rs 1200000000.

 

Q2. The perimeter of a park is 240m. Determine the area.

Ans:       Perimeter = 240 m

4 x Length of a side of the park = 240

Length of a side of park = 240/4 = 60 m

Area = (Length of a side of park) 2 = (60)2 = 3600 m2

 

Q3. The area and length of a rectangular plot of land are 1200 m2 and 40 m respectively. Determine its perimeter.  

Ans:       Area = Length (l) x Breadth (b) = 1200 m2

= 40 x Breadth = 1200

= Breadth = 1200/40 = 30

Perimeter = 2 (Length (l) + Breadth (b) )

= 2 (30 + 40) = 2 (70) = 140 m

 

Q4. Find the breadth and area if the perimeter and length of the rectangular sheet is 120 cm and 40 cm respectively.

Ans:       Perimeter = 2 (Length + Breadth) = 120 cm

2 (40 + Breadth) = 120

40 + b = 60

b = 6O – 40 =20 cm

Area = Length (l) x Breadth (b) = 40 x 20 = 800 cm2

 

Q5. The area of the rectangular park is equal to a square park. If the length of rectangular park measures 80m and the side of the square park is 100 m .Determine the breadth of the rectangular park.

Ans:       Area of the square park = (side of the park)2 = (100)2 = 10000 m2

Area of the rectangular park = Length (l) x Breadth (b) = 10000

80 x Breadth = 10000

Breadth = 125 m

 

Q6. The length and breadth of a wire whose shape is a rectangle are 22 and 40 respectively. The wire is then reshaped into a square. Determine the side of the square and find out which shape encloses more area.

Ans:       Perimeter of the rectangle = Perimeter of the square

2 (Length (l) + Breadth (b)) = 4 x Side

2 (22 + 40) = 4 x Side

2 x 62 = 4 x Side

Side =124/4 = 31 cm

Area of the rectangle = 22 x 40 = 880 cm2

Area of the square = (Side)2 = 31 x 31 = 961 cm2

Therefore, the square shaped wire encloses more area.

 

Q7. If the breadth and perimeter of a rectangle are 40 cm and 120 cm respectively, determine the length and area of the rectangle.

Ans:       Perimeter = 2 (Length (l) + Breadth (b)) = 120

2 (Length + 40) = 120

Length + 40 = 60

Length = 60 – 40 = 20 cm

Area = Length (l) x Breadth (b) = 20 x 40 = 800 cm2

 

Q8. A door is fitted in a wall whose length measures 1 m and breadth measures 2 m. The length and breadth of the wall are 5 m and 3.5 m (in the given figure). The price of white washing the wall is Rs 10 per m2. Find the cost of whitewashing the wall without the door.

8

Ans:       Area of the wall = 5 x 3.5 = 17.5 m2

Area of the door = 2x 1 = 2 m2

Area to be white-washed = 17.5 – 2 = 15.5 m2

Cost of white-washing 1 m2 area = Rs 10

Cost of white-washing 15.5 m2 area = 15.5 x 10 = Rs 155

 

Related Links
Ncert Physics Class 8 Ncert Class 8 Maths Pdf
Maths Ncert For Class 7 Ncert Solutions For Class 9 Maths Pdf Free Download
Ncert Maths 12 Pdf Ncert 9
Cbse Ncert Solutions For Class 9 Science Ncert 12 Physics Pdf
Ncert Sol Class 11 Chem Ncert Chemistry Class 12 Pdf Free Download
Ncert Solution Of Class 7Th Ncert Class 8