Area Problems If the sides of a rectangle are increased by 5%, find the percentage increase in its diagonals. 6% 4% 5% 9% 6% 4% 5% 9% ANSWER EXPLANATION DOWNLOAD EXAMIANS APP According to the formula,Percentage increase in diagonals = 5%
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 ratio of the radii of two circle is 1:3 the radio of their areas is? 1:3 1:6 1:9 None of these 1:3 1:6 1:9 None of these ANSWER EXPLANATION DOWNLOAD EXAMIANS APP The Radio of areas = area of first circle : area of 2nd circle= ?r2 / ?(3r)2= ?r2/ 9 ?r2= 1/9 = 1: 9
Area Problems One diagonal of a rhombus is 60% of the other diagonal. Then, area of the rhombus is how many times the square of the length of the larger diagonal? 3/10 1/5 6/7 2/5 3/10 1/5 6/7 2/5 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let one diagonal be k.Then, other diagonal = (60k/100) = 3k/5 cmArea of rhombus =(1/2) x k x (3k/5) = (3/10) = 3/10 (square of longer diagonal)Hence, area of rhombus is 3/10 times.
Area Problems If the length of diagonal AC of a square ABCD is 5.2 cm then area of the square ABCD is? 15.12 sq.cm 10 sq.cm 13.52 sq.cm 12.62 sq.cm 15.12 sq.cm 10 sq.cm 13.52 sq.cm 12.62 sq.cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Area = 1/2 x (Diagonal)2= (1/2) x 5.2 x 5.2 cm2= 13.52 cm2
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 64 60 68 72 64 60 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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