RS Aggarwal Class 7 Mathematics Twentieth Chapter Mensuration Exercise 20G Solution
EXERCISE 20G
OBJECTIVE QUESTIONS
Mark (√) against the correct answer in each of the following:
(1) The length of a rectangle is 16 cm and the length of its diagonal is 20 cm. The area of the rectangle is
Ans: (c) 192 cm2
(2) Each diagonal of a square is 12 cm long. Its area is
Ans: (b) 72 cm2
(3) The area of a square is 200 cm2. The length of its diagonal is
Ans: (b) 20 cm
(4) The area of a square field is 0.5 hectare. The length of its diagonal is
Ans: (a) 100 m
(5) The length of a rectangular field is thrice its breadth and its perimeter is 240 m. the length of the field is
Ans: (c) 90 m.
(6) On increasing each side of a square by 25%, the increase in area will be
Ans: (d) 56.25%
(7) The area of a square and that of a square drawn on its diagonal are in the ratio
Ans: (b) 1 : 2
(8) The perimeters of a square and rectangle are equal. If their areas be A m2 and B m2, then which of the following is a true statement?
Ans: (c) A > B
Area of the square > Area of the rectangle.
(9) The length and the breadth of a rectangular field are in the ratio 5 : 3 and its perimeter is 480 m. The area of the field is
Ans: (b) 13500 m2
(10) The length of a room is 15 m. The cost of carpeting it with a carpet 75 cm wide at Rs 50 per metre is Rs 6000. The width of the room is
Ans: (a) 6 m
(11) The sides of a triangle measure 13 cm, 14 cm and 15 cm. Its area is
Ans: (a) 84 cm2
(12) The base and height of a triangle are 12 m and 8 m respectively. Its area is
Ans: (b) 48 m2
(13) The area of an equilateral triangle is 4√3 cm2. The length of each of its sides is
Ans: (b) 4 cm
(14) Each side of an equilateral triangle is 8 cm long. Its area is
Ans: (c) 16√3 cm2
(15) The height of an equilateral triangle is √6 cm. Its area is
Ans: (b) 2√3 cm2
(16) One side of a parallelogram is 16 cm and the distance of this side from the opposite side is 4.5 cm. The area of the parallelogram is
Ans: (b) 72 cm2
(17) The lengths of the diagonals of a rhombus are 24 cm and 18 cm respectively. Its area is
Ans: (b) 216 cm2
(18) The difference between the circumference and radius of a circle is 37 cm. the area of the circle is
Ans: (c) 154 cm2
(19) The perimeter of the floor of a room is 18 m and its height is 3 m. What is the area of 4 walls of the room?
Ans: (c) 54 m2
(20) How many metres of carpet 63 cm wide will be required to cover the floor of a room 14 m by 9 m?
Ans: (a) 200 m
(21) If the diagonal of a rectangle is 17 cm long and its perimeter is 46 cm, the area of the rectangle is
Ans: (c) 120 cm2
(22) If the ratio of the area of two squares is 9 : 1, then the ratio of their perimeters is
Ans: (b) 3 : 1
(23) The ratio of the area of two squares, one having its diagonal double that of the other, is
Ans: (d) 4 : 1
(24) The area of a rectangle 144 m long is the same as that of a square of side 84 m. The width of the rectangle is
Ans: (c) 49 m
(25) The ratio of the area of a square of side a and that of an equilateral triangle of side a, is
Ans: (d) 4 : √3
(26) The area of a square is equal to the area of a circle. What is the ratio between the side of the square and the radius of the circle?
Ans: (a) √π : 1
(27) Each side of an equilateral triangle is equal to the radius of a circle whose area is 154 cm2. The area of the triangle is
Ans: (b)
(28) The area of rhombus id 36 cm2 and the length of one of its diagonals is 6 cm. The length of the second diagonal is
Ans: (c) 12 cm
(29) The area of rhombus is 144 cm2and one of its diagonals is double the other. The length of the longer diagonal is
Ans: (d) 24 cm
(30) The area of a circle is 24.64 m2. The circumference of the circle is
Ans: (c) 17.60 m
(31) The area of a circle is increased by 22 cm2 when its radius is increased by 1 cm. The original radius of the circle is
Ans: (c) 3 cm
(32) The radius of a circular wheel is 1.75 m. How many revolutions will in make travelling 11 km?
Ans: (c) 1000
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