Area Problems The area of a rectangle, 144 m long is the same as that of a square having a side 84 m long. The width of the rectangle is? 14 m 49 m 7 m Cannot be determined 14 m 49 m 7 m Cannot be determined ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Area of the square = (84 + 84) m2Area of the rectangle = (144 x width) m2From question both area would be same,? Width = (84 x 84) / 144 m = 49 m
Area Problems Find the length of a rope by which a cow must be tethered in order that it may be able to graze an area of 154 sq m. 13 m 8 m 7 m 12 m 13 m 8 m 7 m 12 m ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Length of to the rope = Radius of circle According to the question,?r2 = 154 ? r2 = 154 x (7/22) = 7 x 7 = 49 ? r = ?49 = 7 m
Area Problems The circumferences of two concentric are 176 m and 132 m respectively. what is the difference between their radii? 44 meter 7 meter 5 meter 8 meter 44 meter 7 meter 5 meter 8 meter ANSWER EXPLANATION DOWNLOAD EXAMIANS APP ? 2?R - 2?r = (176-132)? 2?(R-r) = 44? R-r = ( 44 x 7 )/ (2 x 22)= 7 m
Area Problems The diameter of the driving wheel of a bus is 140 cm. How many revolution, per minute must the wheel make in order to keep a speed of 66 kmph ? 150 350 250 550 150 350 250 550 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Circumference = No.of revolutions * Distance covered Distance to be covered in 1 min. = (66 X1000)/60 m = 1100 m.Circumference of the wheel = 2 x (22/7) x 0.70 m = 4.4 m.Number of revolutions per min. =(1100/4.4) = 250.
Area Problems If the radius of a circle be reduced by 50%. Its area is reduced by? 39.5% 65.5% 31.5% 34.5% 39.5% 65.5% 31.5% 34.5% ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Original area = ? x (r/2)2 = ?r2/4Reduction in area = ? r2 - 3? r2/4? Reduction per cent = [ 3?r2/4 x 4/(?r2) x 100 ] %= 75%
Area Problems A rectangle has 20 cm as its length and 200 sq cm as its area. If the area is increased by 1 1/ 5 time the original area by increase its length only then the perimeter of the rectangle so formed (in cm) is 64 60 72 68 64 60 72 68 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP l1 = 20 cm, A1 = 200 sq cm? b1 = 200/20 = 10 cmNow, A2 = 200 x 6/5 = 240 sq cm b2 = 10 cm? l2 = 240/10 = 24 cm? Perimeter of new rectangle = 2(l2 + b2)= 2(24 + 10) = 2 x 34 = 68 cm
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