Area Problems One side of a rectangular field is 4 meter and its diagonal is 5 meter. The area of the field is? 15 m2 4?5 m2 20 m 2 12 m2 15 m2 4?5 m2 20 m 2 12 m2 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Other side = ?5 2 - 42 = ? 9=3 mSo The area of the rectangular field = 4 x 3 = 12 m2
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 60 64 72 68 60 64 72 68 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
Area Problems The length of a rectangle is halved, while its breadth is tripled. What is the percentage change in area? 50% increase 75% decrease 50% decrease 25% increase 50% increase 75% decrease 50% decrease 25% 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 Find the perimeter of a triangle with sides equal to 6 cm, 4 cm and 5 cm. 18 cm 14 cm 20 cm 15 cm 18 cm 14 cm 20 cm 15 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Given that, a = 6 cm, b = 4 cm and c = 5 cm Required perimeter = a + b + c= 6 + 4 + 5 cm = 15 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 50 cm 70 cm 60 cm 80 cm 50 cm 70 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
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
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