Area Problems The ratio of the corresponding sides of two similar triangles is 3 : 4, The ratio of their areas is? ? 3: 2 4 : 3 9 : 16 3 : 4 ? 3: 2 4 : 3 9 : 16 3 : 4 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Ratio of similar triangle = Ratio of the square of corresponding sides = (3x)2 / (4x)2 = 9x2 / 16x2 = 9/16 = 9 : 16
Area Problems The diagonal of a rectangle is √41 cm and its area is 20 sq. cm. The perimeter of the rectangle must be: 41 cm 9 cm 18 cm 20 cm 41 cm 9 cm 18 cm 20 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 diameters of a circle is increased by 100% . Its area is increased by? 100% 200% 400% 300% 100% 200% 400% 300% ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Original area = ?(d/2)2= (?d2) / 4New area = ?(2d/2)2= ?d2Increase in area = (?d2 - ?d2/4)= 3?d2/4? Required increase percent = [(3?d2)/4 x 4/(?d2) x 100]%= 300%
Area Problems The inner circumference of a circular race track, 14 m wide is 440 m . Then the radius of the outer circle is? 77 m 84 m 70 m 56 m 77 m 84 m 70 m 56 m ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Circumference of a circular = 2?r? 2 x (22 / 7) x r = 440? r = [440 x (7/22) x (1/2)] = 70 m? Radius of outer circle = (70 + 14) m = 84 m
Area Problems The ratios of areas of two squares, one having its diagonal double than the other is 3:1 2:1 4:1 2:3 3:1 2:1 4:1 2:3 ANSWER DOWNLOAD EXAMIANS APP
Area Problems The circumferences of two concentric are 176 m and 132 m respectively. what is the difference between their radii? 7 meter 8 meter 44 meter 5 meter 7 meter 8 meter 44 meter 5 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
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