Area Problems A tank is 25m long 12m wide and 6m deep. The cost of plastering its walls and bottom at 75 paise per sq m is Rs. 558 Rs. 458 Rs. 258 Rs. 358 Rs. 558 Rs. 458 Rs. 258 Rs. 358 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Area to be plastered = 2 l + b × h + l × b = 2 25 + 12 × 6 + 25 × 12 = 744 s q . m Cost of plastering = 744 × 75 100 = R s . 558
Area Problems A circular disc of area 0.49 ? square meters, rolls down a length of 1.76 km. The number of revolutions it makes is? 400 4000 300 600 400 4000 300 600 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Area = ?r2 = 0.49? ? r = 0.7 mNumber of revolutions = total distance / circumference = (1.76 x 1000) / (2 x 22/7 x 0.7) = 400
Area Problems The altitude of an equilateral triangle of side 2 ? 3 cm is? ? 3/4 ? 3/2 cm 3 cm 1/2 cm ? 3/4 ? 3/2 cm 3 cm 1/2 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP ? 1/2 x 2 ? x h = ?3/4 x (2 ?3)2? h = 3 cm.
Area Problems A park is in the form of a square one of whose sides is 100 m . The area of the park excluding the circular lawn in the centre of the park is 8614 m 2. The radius of the circular lawn is? 21 m 41 m None of these 31 m 21 m 41 m None of these 31 m ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Area of park = 100 x 100 = 10000 m2Area of circular lawn = Area of park - area of park excluding circular lawn= 10000 - 8614 = 1386Now again area of circular lawn = (22/7) x r2 = 1386 m2? r2 = (1386 x 7) / 22= 63 x 7= 3 x 3 x 7 x 7? r = 21 m
Area Problems A triangle with three equal sides has its area equal to 3?3 sq cm . Find its perimeter . 7?3 cm 5?3 cm 2?3 cm 6?3 cm 7?3 cm 5?3 cm 2?3 cm 6?3 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP According to the question,?3a2/4 = 3?3 [ side = a, and area = ?3a2/4] ? a2/4 = 3 ? a2 = 3 x 4 ? a = 2?3? Required perimeter = 3a =3 x 2?3 = 6?3 cm
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 64 72 60 68 64 72 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
EXAMIANS