EXERCISE 11.1
"Perimeter and Area" Chapter 11 - Introduction - NCERT Class 7th Maths Solutions
Q 1, Ex 11.1 - Perimeter and Area - Chapter 11 - Maths Class 7th - NCERT
Page No 208:
Question 1:
The length and the breadth of a rectangular piece of land are 500 m and 300 m respectively. Find(i) its area
(ii)the cost of the land, if 1 m2 of the land costs Rs 10,000.
Answer:
(i) Area = Length × Breadth= 500 × 300
= 150000 m2
(ii)Cost of 1 m2 land = Rs 10000
Cost of 150000 m2 land = 10000 × 150000 = Rs 1500000000
Q 2, Ex 11.1 - Perimeter and Area - Chapter 11 - Maths Class 7th - NCERT
Question 2:
Find the area of a square park whose perimeter is 320 m.Answer:
Perimeter = 320 m4 × Length of the side of park = 320
Length of the side of park =
Area = (Length of the side of park)2 = (80)2 = 6400 m2
Q 3, Ex 11.1 - Perimeter and Area - Chapter 11 - Maths Class 7th - NCERT
Question 3:
Find the breadth of a rectangular plot of land, if its area is 440 m2 and the length is 22 m. Also find its perimeter.Answer:
Area = Length × Breadth = 440 m222 × Breadth = 440
Breadth =
= 20 mPerimeter = 2 (Length + Breadth)
= 2 (22 + 20) = 2 (42) = 84 m2
Question 4:
The perimeter of a rectangular sheet is 100 cm. If the length is 35 cm, find its breadth. Also find the area.Answer:
Perimeter = 2 (Length + Breadth) = 100 cm2 (35 + Breadth) = 100
35 + B = 50
B = 50 − 35 = 15 cm
Area = Length × Breadth = 35 × 15 = 525 cm2
Question 5:
The area of a square park is the same as of a rectangular park. If the side of the square park is 60 m and the length of the rectangular park is 90 m, find the breadth of the rectangular park.Answer:
Area of square park = (One of its sides)2 = (60)2 = 3600 m2Area of rectangular park = Length × Breadth = 3600
90 × Breadth = 3600
Breadth = 40 m
Q 6, Ex 11.1 - Perimeter and Area - Chapter 11 - Maths Class 7th - NCERT
Question 6:
A wire is in the shape of a rectangle. Its length is 40 cm and breadth is 22 cm. If the same wire is rebent in the shape of a square, what will be the measure of each side. Also find which shape encloses more area?Answer:
Perimeter of rectangle = Perimeter of square2 (Length + Breadth) = 4 × Side
2 (40 + 22) = 4 × Side
2 × 62 = 4 × Side
Side =
= 31 cmArea of rectangle = 40 × 22 = 880 cm2
Area of square = (Side)2 = 31 × 31 = 961 cm2
Therefore, the square-shaped wire encloses more area.
Q 7, Ex 11.1 - Perimeter and Area - Chapter 11 - Maths Class 7th - NCERT
Question 7:
The perimeter of a rectangle is 130 cm. If the breadth of the rectangle is 30 cm, find its length. Also find the area of the rectangle.Answer:
Perimeter = 2 (Length + Breadth) = 1302 (Length + 30) = 130
Length + 30 = 65
Length = 65 − 30 = 35 cm
Area = Length × Breadth = 35 × 30 = 1050 cm2
Q 8, Ex 11.1 - Perimeter and Area - Chapter 11 - Maths Class 7th - NCERT
Question 8:
A door of length 2 m and breadth 1 m is fitted in a wall. The length of the wall is 4.5 m and the breadth is 3.6 m (see the given figure). Find the cost of white washing the wall, if the rate of white washing the wall is Rs 20 per m2.
Answer:
Area of wall = 4.5 × 3.6 = 16.2 m2Area of door = 2 × 1 = 2 m2
Area to be white-washed = 16.2 − 2 = 14.2 m2
Cost of white-washing 1 m2 area = Rs 20
∴Cost of white-washing 14.2 m2 area = 14.2 × 20 = Rs 284
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