Area Problems The area of an equilateral triangle is ? 243 /4 sq cm. Find the length of its side. 3?3 cm 9 cm ?3 cm 3 cm 3?3 cm 9 cm ?3 cm 3 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP According to the question,area = ?3a2/4 = ?243 /4? a2 = ?81 x 3/?3 ? a = ?9 = 3 cm
Area Problems The length of a rectangle is double while its breadth is halved. What is the percentage change in area? 50 No change 75 None of these 50 No change 75 None of these ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let length = l and breadth = bThen, area = lb New length = 2lAnd new breadth = b/2 ? New area = ( 2l ) x (b/2) = lbSo, there is no change in area .
Area Problems A rectangle has 15 cm as its length and 150 cm 2 as its area .Its area is increased to 1 1 / 3 times the original area by increasing only its length . Its new perimeter is? 70 cm 60 cm 80 cm 50 cm 70 cm 60 cm 80 cm 50 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Breadth of the rectangle = (150/15) cm= 10 cmNew area = (4/3 x 150) cm2= 200 cm2New length = 200/10 cm=20 cmNew perimeters = 2(20 + 10) cm= 60 cm
Area Problems The sides of a triangular board are 13 meters, 14 meters and 15 meters. The cost of paining it at the rate of Rs. 8.75 per m 2 is? Rs. 722.50 Rs. 735 Rs. 688.80 Rs. 730.80 Rs. 722.50 Rs. 735 Rs. 688.80 Rs. 730.80 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP s = (13 + 14 + 15 ) / 2 = 21, s-a = 8 , s-b = 7, s-c= 6? Area to be painted = ? [s(s-a) (s-b) (s-c)]=? [21 x 8 x 7 x 6] m2= 84 m2? Cost of painting = Rs. (84 x 8.75) = Rs. 735
Area Problems The perimeter of an isosceles triangle is 26 cm while equal sides together measure 20 cm. The third side and each of the equal sides are respectively. 10 cm and 8 cm 6 cm and 10 cm 8 cm and 9 cm 14 cm and 6 cm 10 cm and 8 cm 6 cm and 10 cm 8 cm and 9 cm 14 cm and 6 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the third side be x.According to the question,x + 20 = 26? x = 26 - 20 = 6 cm ? Each equal side = 20/2 = 10 cm
Area Problems The area of a trapezium is 384 sq.cm 2. If its parallel sides are in ratio 3 : 5 and the perpendicular distance between them be 12 cm, The smaller of parallel sides is? 36 cm 30 cm 20 cm 24 cm 36 cm 30 cm 20 cm 24 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the sides of trapezium be 5k and 3k, respectively According to the question, (1/2) x [(5k + 3k) x 12] = 384? 8k = (384 x 2)/12 = 64 ? k = 64/8 = 8 cmLength of smaller of the parallel sides = 8 x 3 = 24 cm
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