Area Problems If the diagonals of a rhombus are 4.8 cm 1.4 cm, then what is the perimeter of the rhombus? 12 cm 20 cm 5 cm 10 cm 12 cm 20 cm 5 cm 10 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 the diagonal of a square is double, how does the area of the square change? Becomes two fold None of these Becomes three fold Becomes four fold Becomes two fold None of these Becomes three fold Becomes four fold ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Ratio of the areas = area of original square / area of new square = [ d2 / 2 ] / [ (2d)2 / 2 ] = 1/4? New area becomes 4 fold.
Area Problems The area of an equilateral triangle whose side is 8 cms is? 4?3 cm2 21.3 cm2 16?3 cm2 64 cm2 4?3 cm2 21.3 cm2 16?3 cm2 64 cm2 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Req. Area = ?3/4 x a2 = ?3/4 x 82 cm2= 16?3 cm2
Area Problems If the radius of a circle is decreased by 50% , find the percentage decrease in its area. 35% 75% 25% 65% 35% 75% 25% 65% ANSWER EXPLANATION DOWNLOAD EXAMIANS APP let original radius = r and new radius = (50/100) r = r/2 original area = ?r 2 and new area = ? r / 2 2 decrease in area = 3 ?r 2 / 4 * 1 ?r 2 *100 = 75%
Area Problems The radius of a circular field is 25 m. Find the area of the field. 135 ? sq m 25 ? sq m 125 ? sq m 625 ? sq m 135 ? sq m 25 ? sq m 125 ? sq m 625 ? sq m ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Required area = ?r2 = ? x 25 x 25 = 625? sq m.
Area Problems The length of a rectangle is double while its breadth is halved. What is the percentage change in area? 75 50 None of these No change 75 50 None of these No change 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 .
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