Area Problems The radius of a circular field is 25 m. Find the area of the field. 125 ? sq m 135 ? sq m 25 ? sq m 625 ? sq m 125 ? sq m 135 ? sq m 25 ? sq m 625 ? sq m ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Required area = ?r2 = ? x 25 x 25 = 625? sq m.
Area Problems The ratio between the length and the breadth of a rectangular park is 3 : 2. If a man cycling along the boundary of the park at the speed of 12 km/hr completes one round in 8 minutes, then the area of the park (in sq. m) is: 15360 30720 307200 153600 15360 30720 307200 153600 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Perimeter = Distance covered in 8 min. = ❨ 12000 x 8 ❩m = 1600 m. 60 Let length = 3x metres and breadth = 2x metres. Then, 2(3x + 2x) = 1600 or x = 160. ∴ Length = 480 m and Breadth = 320 m. ∴ Area = (480 x 320) m2 = 153600 m2
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 72 60 64 68 72 60 64 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
Area Problems An error 2% in excess is made while measuring the side of a square. The percentage of error in the calculated area of the square is: 2.02% 4.04% 2% 4% 2.02% 4.04% 2% 4% ANSWER EXPLANATION DOWNLOAD EXAMIANS APP 100 cm is read as 102 cm. ∴ A1 = (100 x 100) cm2 and A2 (102 x 102) cm2. (A2 - A1) = [(102)2 - (100)2] = (102 + 100) x (102 - 100) = 404 cm2. ∴ Percentage error = ❨ 404 x 100 ❩% = 4.04%
Area Problems The Number of rounds that a wheel of diameter 7/11 m will make in going 4 km, is? 1700 1500 2000 1000 1700 1500 2000 1000 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Number of round = total distance / circumference of wheel.= (4 x 1000) / ?d= (4 x 1000) / ( 22/7 x 7/11) = 2000
Area Problems The ratio of the area of a square to that of the square drawn on its diagonal is 4:1 3:1 2;3 1:2 4:1 3:1 2;3 1:2 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP atio = a 2 2 a 2
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