Area Problems The ratio of the radii of two circle is 1:3 the radio of their areas is? 1:9 None of these 1:6 1:3 1:9 None of these 1:6 1:3 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 The length of a rectangle is halved, while its breadth is tripled. What is the percentage change in area? 25% increase 75% decrease 50% decrease 50% increase 25% increase 75% decrease 50% decrease 50% increase ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let original length = x and original breadth = y. Original area = xy. New length = x . 2 New breadth = 3y. New area = ❨ x x 3y ❩ = 3 xy. 2 2 ∴ Increase % = ❨ 1 xy x 1 x 100 ❩% = 50%
Area Problems if the side of a square be increased by 4 cms. The area increased by 60 sq. cms . The side of the square is? 12 cm 14cm 13 cm None of these 12 cm 14cm 13 cm None of these ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let each side = x cmThen, (x + 4 )2 - x2 = 60? x 2 + 8x + 16 - x2 = 60? x = 5.5 cm
Area Problems The diagonal of the floor of a rectangular closet is 7½ feet. The shorter side of the closet is 4½ feet. What is the area of the closet in square feet? 13(1/2) 27 37 5(1/4) 13(1/2) 27 37 5(1/4) ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Other side = (15 / 2) 2 - (9 / 2) 2 ft = (225 / 4) - (81 / 4) ft = 144 / 4 ft = 6 ft Area of closet = (6 x 4.5) sq. ft = 27 sq. ft.
Area Problems The length of a rectangle is twice its breadth. If its length is decreased by 5 cm and the breadth is increased by 5 cm, the area of the rectangle is increased by 75 cm 2 . Therefore , the length of the rectangle is? 40 cm 20 cm 30 cm 50 cm 40 cm 20 cm 30 cm 50 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let breadth = b, length = 2b? Area of rectangle = 2b x b = 2b2As per question. ? (2b - 5 ) (b + 5 ) = 2b2 + 75? 5b = 75 + 25? 5b = 100? b = 100 / 5 = 20Hence, length of the rectangle =2b = 2 x 20 = 40 cm.
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? 80 cm 70 cm 50 cm 60 cm 80 cm 70 cm 50 cm 60 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
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