Area

21 The length of rectangle is increased by 60%. By what per cent would the width have to be decreased so as to maintain the same area?

22 A circle and a rectangle have the same perimeter. The sides of the rectangle are 18 cm and 26 cm. What is the area of the circle?

23 The perimeter of a square is twice the perimeter of a rectangle. If the perimeter of the square is 72 cm and the length of the rectangle is 12 cm, what is the difference between the breadth of the rectangle and the side of the square?

24 The radius of a circular wheel is 1 $$\frac{3}{4}$$ m. How many revolutions will it make in travelling 11 km?

25 Find the length of the altitude of an equilateral triangle of side 9V3 cm:

26 If every side of a triangle is doubled, the area of the new triangle is K times the area of the old one. K is equal to

27 A park square in shape has a 3 m wide road inside it running along it's sides. The area occupied by the road is 1764 m°. What is the perimeter along the outer edge of the road?

28 Area of a rectangular field is 3584 m and the length and the breadth are in the ratio 7 : 2, respectively. What is the perimeter of the rectangle?

29 Find the cost of carpeting a room 8 m long and 6 m broad with a carpet 75 cm wide at ₹ 20 per m:

30 Floor of a square room of side 10 m is to be completely covered with square tiles, each having length 50 cm. The smallest number of tiles needed is