Question 11 Mark
To find the cost of painting a wall we need to find the perimeter of the wall.
Answer
View full question & answer→False. Solution: To find the cost of painting a wall we need to find the area of the wall.
Questions
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Question 21 Mark
An engineer who plans to build a compound wall on all sides of a house must find the area of the compound.
Answer
View full question & answer→False. Solution: He must find the perimeter of the compound.
Question 31 Mark
Area of a rectangle with length $5\ cm$ and breadth $3\ cm$ is _________.
Answer
View full question & answer→Area of a rectangle with length $5\ cm$ and breadth $3\ cm$ is $15\ cm^2$.
Area = Length $\times$ Breadth $= 5 \times 3 = 15\ cm^2$
Area = Length $\times$ Breadth $= 5 \times 3 = 15\ cm^2$
Question 41 Mark
Perimeter of the shaded portion in Fig. is:
$ AB + + + + + + + HA$
$ AB + + + + + + + HA$
Answer
View full question & answer→$AB + BM + MD + DE + EN + NG + GH + HA$
Solution: Perimeter of the shaded portion = Sum of all sides $= AB + BM + MD + DE + EN + NG + GH + HA$
Solution: Perimeter of the shaded portion = Sum of all sides $= AB + BM + MD + DE + EN + NG + GH + HA$
Question 51 Mark
If length of a rectangle is halved and breadth is doubled then the area of the rectangle obtained remains same.
Answer
View full question & answer→New area $=\Big(\frac{1}{2}\Big)\times2\text{b}=\text{l}\times\text{b}=\text{Old area}$
Question 61 Mark
A rectangle and a square have the same perimeter.
$a.$ The area of the rectangle is $....$
$b.$ The area of the square is $......$
$a.$ The area of the rectangle is $....$
$b.$ The area of the square is $......$
Answer
View full question & answer→
$a.$ The area of the rectangle is $12$sq units.
$b.$ The area of the square is $16$sq units.
Solution:
$a.$ Given, length of rectangle $= 6$ units
and breadth of rectangle $= 2$ units
$\therefore$ Area of a rectangle = Length $x$ Breadth $= 6 \times 2 = 12$sq units
$b.$ According to question,
Perimeter of square $=$ Perimeter of rectangle
$\Rightarrow 4 \times $ Side $= 2 \times ($Length $+$ Breadth$)$
$\Rightarrow 4 \times $ Side $= 2 \times (6 + 2)$
$\Rightarrow 4 \times $ Side $= 2 \times 8$
$\Rightarrow 4 \times $ Side $= 16$
$\Rightarrow\frac{4\times\text{Side}}{4}=\frac{16}{4}$ [dividing both sides by $4]$
$\therefore$ Side $= 4$ units
Now, area of square = Side $\times $ Side $= 4 \times 4 = 16$sq units
$b.$ The area of the square is $16$sq units.
Solution:
$a.$ Given, length of rectangle $= 6$ units
and breadth of rectangle $= 2$ units
$\therefore$ Area of a rectangle = Length $x$ Breadth $= 6 \times 2 = 12$sq units
$b.$ According to question,
Perimeter of square $=$ Perimeter of rectangle
$\Rightarrow 4 \times $ Side $= 2 \times ($Length $+$ Breadth$)$
$\Rightarrow 4 \times $ Side $= 2 \times (6 + 2)$
$\Rightarrow 4 \times $ Side $= 2 \times 8$
$\Rightarrow 4 \times $ Side $= 16$
$\Rightarrow\frac{4\times\text{Side}}{4}=\frac{16}{4}$ [dividing both sides by $4]$
$\therefore$ Side $= 4$ units
Now, area of square = Side $\times $ Side $= 4 \times 4 = 16$sq units
Question 71 Mark
$1sqm = 1m \times m = 100\ cm \times \ cm.$
Answer
View full question & answer→$1sqm = 1m \times 1m = 100\ cm \times 100cm.$
Question 81 Mark
Area of a square is doubled if the side of the square is doubled.
Answer
View full question & answer→ False.
Solution:
Area becomes four times.Question 91 Mark
A farmer who wants to fence his field, must find the perimeter of the field.
Answer
View full question & answer→True. Solution: Since, perimeter is the measure of the boundary.
Question 101 Mark
$1sqm = sqcm.$
Answer
View full question & answer→$1sqm = 1000sqcm.$
Question 111 Mark
$1m = $______$ \ cm.$
Answer
View full question & answer→$1m = 100\ cm.$
Question 121 Mark
The amount of region enclosed by a plane closed figure is called its _________.
Answer
View full question & answer→The amount of region enclosed by a plane closed figure is called its area.
Question 131 Mark
$1sqcm = \ cm \times 1\ cm.$
Answer
View full question & answer→$1sqcm = 1\ cm \times 1\ cm.$
Question 141 Mark
To find the cost of a frame of a picture, we need to find the perimeter of the picture.
Answer
View full question & answer→True.Solution:
Length of frame = Perimeter
Length of frame = Perimeter
Question 151 Mark
The perimeter of a square garden is $48m$. A small flower bed covers $18$sq-m area inside this garden. What is the area of the garden that is not covered by the flower bed? What fractional part of the garden is covered by flower bed? Find the ratio of the area covered by the flower bed and the remaining area.
Answer
View full question & answer→Perimeter of the regular octagon $= 8 \times $ Side of the octagon $= 8 \times 6 = 48\ cm$