Area Problems If the radius of a circle is increased by 6%, find the percentage increase in its area. 15% 8.39% 17% 12.36% 15% 8.39% 17% 12.36% ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Given that, a = 6 According to the formula,Percentage increase in area= 2a + [a2/100]%= 2 x 6 + [36/100]%= (12 + 0.36)%= 12.36%
Area Problems A wheel make 4000 revolution in moving a distance of 44 km. Find the radius of the wheel. 28 m 25 m 27 m 1.75 m 28 m 25 m 27 m 1.75 m ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Distance covered in 1 revolution = (44 x 1000) / 4000 = 11 mAccording to the question, 2?r = 11 ? (44/7) x r = 11? r = (11 x 7) / 44 = 1.75 m
Area Problems A circular wire of radius 42 cm is cut and bent in the form of a rectangle whose sides are in the ratio of 6: 5 . The smaller side of the rectangle is? 72 cm 60 cm 30 cm 132 cm 72 cm 60 cm 30 cm 132 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Perimeter of rectangle = Circumference of circle = 2?r=2 x ( 22/7 ) x 42= 264 cm Now perimeter of rectangle = 2 x ( 6a + 5a )? 2 x (6a + 5a) = 264? a = 12Smaller side of rectangle = 5a = 60 cm
Area Problems The diagonal of a rectangle is √41 cm and its area is 20 sq. cm. The perimeter of the rectangle must be: 9 cm 41 cm 20 cm 18 cm 9 cm 41 cm 20 cm 18 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP √l2 + b2 = √41. Also, lb = 20. (l + b)2 = (l2 + b2) + 2lb = 41 + 40 = 81 ⟹ (l + b) = 9. ∴ Perimeter = 2(l + b) = 18 cm
Area Problems If the diagonal of a rectangle is 17cm long and its perimeter is 46 cm. Find the area of the rectangle. 130 110 120 140 130 110 120 140 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP let length = x and breadth = y then 2(x+y) = 46 => x+y = 23 x²+y² = 17² = 289 now (x+y)² = 23² => x²+y²+2xy= 529 => 289+ 2xy = 529 => xy = 120 area = xy = 120 sq.cm
Area Problems The length of hall is (4/3) times its breadth. If the area of hall be 300 square meters, the difference between the length and the breadth is? 4 meters 15 meters None of these 3 meters 4 meters 15 meters None of these 3 meters ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let breadth = b meters.Then, length = 4b/3 meters.? b x 4b/3 = 300? b2 = 300 x 3/4 ? b2 = 225? b = 15Hence, required difference = [(Length) - (Breadth) ]= 4b/3 - b = b/3= 15/3 m= 5 m
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