are 12.3 cm
8
Length
th and breadth of a rectangle
and .6 cm respectively, find its perimeter.
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Answers
Answer:
The length and 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:
Given: Length of a rectangular piece of land = 500 m
and breadth of a rectangular piece of land = 300 m
(i) Area of a rectangular piece of land = Length * Breadth
= 500 * 300
= 1,50,000 m2
(ii) Since, the cost of 1 m2 land = Rs 10,000
Therefore, the cost of 1,50,000 m2 land = 10,000 * 1,50,000 = Rs 1,50,00,00,000
Question 2:
Find the area of a square park whose perimeter is 320 m.
Answer:
Given: Perimeter of square park = 320 m
=> 4 * side = 320
=> side = 320/4 = 80 m
Now, Area of square park = side * side = 80 * 80 = 6400 m2
Thus, the area of the square park is 6400 m2.
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 of rectangular park = 440 m2
=> length * breadth = 440 m2
=> 22 * breadth = 440
=> breadth = 440/22 = 20 m
Now, Perimeter of rectangular park = 2(length + breadth)
= 2(22 + 20)
= 2 * 42 = 84 m
Thus, the perimeter of rectangular park is 84 m.
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 of the rectangular sheet = 100 cm
=> 2(length + breadth) = 100 cm
=> 2(35 + breadth) = 100
=> 35 + breadth = 100/2
=> 35 + breadth = 50
=> breadth = 50 - 35
=> breadth = 15 cm
Now, Area of rectangular sheet = length * breadth
= 35 * 15 = 525 cm2
Thus, breadth and area of rectangular sheet are 15 cm and 525 cm2 respectively.
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 cm,
find the breadth of the rectangular park.
Answer:
Given: The side of the square park = 60 m
The length of the rectangular park = 90 m
According to the question,
Area of square park = Area of rectangular park
=> side * side = length * breadth
=> 60 * 60 = 90 * breadth
=> 3600 = 90 * breadth
=> breadth = 3600/90 = 40 m
Thus, the breadth of the rectangular park is 40 m.
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:
According to the question,
Perimeter of square = Perimeter of rectangle
=> 4 * side = 2(length + breadth)
=> 4 * side = 2(40 + 22)
=> 4 * side = 2 * 62
=> 4 * side = 124
=> side = 124/4
=> side = 31 cm
Thus, the side of the square is 31 cm.
Now, Area of rectangle = length * breadth = 40 * 22 = 880 cm2
and area of square = side * side = 31 * 31 = 961 cm2
Therefore, on comparing, the area of square is greater than that of rectangle.
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 of rectangle = 130 cm
=> 2(length + breadth) = 130 cm
=> 2(length + 30) = 130
=> length + 30 =130/2
=> length + 30 = 65
=> length = 65 – 30 = 35 cm
Now area of rectangle = length * breadth = 35 * 30 = 1050 cm2
Thus, the area of rectangle is 1050 cm2.
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.
Find the cost of white washing the wall, if the rate of white washing the wall is Rs 20 per m2.
Class_7_Perimeter_&_Area_Area_Of_Door_Fitted_In_A_Wall
Answer:
Area of rectangular door = length * breadth = 2 m * 1 m = 2 m2
Area of wall including door = length * breadth = 4.5 m * 3.6 m = 16.2 m2
Now, Area of wall excluding door = Area of wall including door – Area of door
= 16.2 – 2 = 14.2 m2
Since the rate of white washing of 1 m2 the wall = Rs 20
Therefore, the rate of white washing of 14.2 m2 the wall = 20 * 14.2 = Rs 284
Thus, the cost of white washing the wall excluding the door is Rs 284.