Area Problems If the side of a square is increased by 25%, then how much percent does its area get increased? 50 156.25 56.25 125 50 156.25 56.25 125 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let area 100 m2Then, side = 10 m New side = 125 % of 10= (125/100) x 10= 12.5 m New area = 12.5 x 12.5 m2=(12.5)2 sq. m? Increase in area = (12.5)2 - (10)2 m2= 22.5 x 2.5 m2=56.25 m2% Increase = 56.25 %
Area Problems If the diagonals of a rhombus are 4.8 cm 1.4 cm, then what is the perimeter of the rhombus? 20 cm 10 cm 12 cm 5 cm 20 cm 10 cm 12 cm 5 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Perimeter of rhombus= 2 ? d12 + d22 = 2 ?(4.8)2 + (1.4)2= 2 ?23.04 + 1.96 = 2 ?25 = 2 x 5 = 10 cm
Area Problems If a regular hexagon is inscribed in a circle of radius, r then its perimeter? 3r 9r 6r 12r 3r 9r 6r 12r ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Length of each side of hexagoan = radius of circle ? its perimeter = 6r
Area Problems The wheel of an engine turns 350 times round its axle to cover a distance of 1.76 km. The diameter of the wheel is 9 cm 3?3 cm ?3 cm 3 cm 9 cm 3?3 cm ?3 cm 3 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Distance covered in 1 round = (Total Distance) / (Total round)= (1.76 x 1000)/350= 176/35 m ? 2?r = (1.76 x 100) / 35 cm2? = Diameter = 17600 x 7/22 x 35 = 160 cm
Area Problems The inner circumference of a circular race track, 14 m wide is 440 m . Then the radius of the outer circle is? 56 m 84 m 70 m 77 m 56 m 84 m 70 m 77 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 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 68 72 60 64 68 72 60 64 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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