Area Problems The radius of the wheel of a vehicle is 70 cm. The wheel makes 10 revolutions in 5 seconds. The speed of the vehicle is? 31.68 km/hr. 32.72 km/hr. 36.25 km/hr. 29.46 km/hr. 31.68 km/hr. 32.72 km/hr. 36.25 km/hr. 29.46 km/hr. ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Circumference = 2?r = 2 x (22 / 7) x 70 cm = 440 cm Distance travelled in 10 revolutions = 440 x 10 cm = 4400 cm = 44 m? Speed = distance / time= 44 / 5 m/sec= (44 / 5) x (18 / 5) km/hr = 31.68 km/hr
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. 358 Rs. 458 Rs. 258 Rs. 558 Rs. 358 Rs. 458 Rs. 258 Rs. 558 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 The diagonal of a rectangle is √41 cm and its area is 20 sq. cm. The perimeter of the rectangle must be: 9 cm 20 cm 41 cm 18 cm 9 cm 20 cm 41 cm 18 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP √l2 + b2 = √41. Also, lb = 20. (l + b)2 = (l2 + b2) + 2lb = 41 + 40 = 81 ⟹ (l + b) = 9. ∴ Perimeter = 2(l + b) = 18 cm
Area Problems The diagonals of two squares are in the ratio of 3 : 2. Find the ratio of their areas. 9 : 2 9 : 7 9 : 5 9 : 4 9 : 2 9 : 7 9 : 5 9 : 4 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the diagonals of the squares be 3x and 2x.? Ratio of their areas = [(1/2) (3x2)] / [(1/2) (2x2)] = 9/4
Area Problems The area of a circle of radius 5 is numerically what percent its circumference? 450% 350% 150% 250% 450% 350% 150% 250% ANSWER DOWNLOAD EXAMIANS APP
Area Problems The area of a trapezium is 384 sq.cm 2. If its parallel sides are in ratio 3 : 5 and the perpendicular distance between them be 12 cm, The smaller of parallel sides is? 36 cm 24 cm 20 cm 30 cm 36 cm 24 cm 20 cm 30 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the sides of trapezium be 5k and 3k, respectively According to the question, (1/2) x [(5k + 3k) x 12] = 384? 8k = (384 x 2)/12 = 64 ? k = 64/8 = 8 cmLength of smaller of the parallel sides = 8 x 3 = 24 cm
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