Area and Perimeter
- The length and breadth of a playground are 36 m and 21 m respectively. Flagstaffs are required to be fixed on all along the boundary at a distance of 3 m apart. The number of flagstaffs will be?
-
View Hint View Answer Discuss in Forum
Perimeter = 2 x (36 + 21 )m = 144 m
∴ Number of flagstaffs = 144 / 3
Correct Option: B
Perimeter = 2 x (36 + 21 ) m = 144 m
∴ Number of flagstaffs = 144 / 3 = 38
- The length of a rectangular plot is twice of its width. If the length of a diagonal is 9√5 meters, the perimeter of the rectangular is ?
-
View Hint View Answer Discuss in Forum
Let breadth = y meters,
Then, length = 2y meters
∴ Diagonal = √y2 + (2y)2
= √5y2 meters
So, √5y2 = 9 √5
∴ y= 9Correct Option: B
Let breadth = y meters,
Then, length = 2y meters
∴ Diagonal = √y2 + (2y)2
= √5y2 meters
So, √5y2 = 9 √5
∴ y= 9
Thus, breadth = 9 m and length = 18 m
∴ Perimeter = 2 (18 + 9) m = 54m.
- A veranda 40 meters long 15 meters broad is to paved with stones each measuring 6 dm by 5 dm. the number of stones required is ?
-
View Hint View Answer Discuss in Forum
Length = (40 x 10 ) dm = 400 dm.
Breadth = (15 x 10 ) dm = 150 dm.
Area of veranda = (400 x 150 ) dm2
Area of one stone = (6 x 5 ) dm2Correct Option: B
Length = (40 x 10 ) dm = 400 dm.
Breadth = (15 x 10 ) dm = 150 dm.
Area of veranda = (400 x 150 ) dm2
Area of one stone = (6 x 5 ) dm2
∴ Required number of stones = (400 x 150) /(6 x 5) = 2000
- if the side of a square be increased by 4 cms. The area increased by 60 sq. cms . The side of the square is ?
-
View Hint View Answer Discuss in Forum
Let each side = x cm
Then, (x + 4 )2 - x2 = 60Correct Option: D
Let each side = x cm
Then, (x + 4 )2 - x2 = 60
⇒ x 2 + 8x + 16 - x2 = 60
∴ x = 5.5 cm
- If the side of a square is increased by 25%, then how much percent does its area get increased ?
-
View Hint View Answer Discuss in Forum
Let area 100 m2
Then, side = 10 m
New side = 125 % of 10
= (125/100) x 10)
= 12.5 m
New area = 12.5 x 12.5 m2
=(12.5)2 sq. mCorrect Option: D
Let area 100 m2
Then, side = 10 m
New side = 125 % of 10
= (125/100) x 10
= 12.5 m
New area = 12.5 x 12.5 m2
=(12.5)2 sq. m
∴ Increase in area = (12.5)2 - (10)2 m2
= 22.5 x 2.5 m2
=56.25 m2
% Increase = 56.25 %