Area Problems The radius of a circle has been reduced from 9 cm to 7 cm . the appropriate percentage decrease in area is? 31.5 % 34.5 % 39.5 % 65.5 % 31.5 % 34.5 % 39.5 % 65.5 % ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Original area = (22/7) x 9 x 9 cm2New area = (22/7) x 7 x 7 cm2? Decrease = 22/7 x [(9)2 -(7)2] cm2=(22/7) x 16 x 2 cm2Decrease percent = [(22/7 x 16 x 2) /( 7/22 x 9 x 9)] x 100 %= 39.5 %
Area Problems A circle and a square have same area. The ratio of the side of the square and the radius of the circle is? 1 : ?? ?? : 1 1 : ? ? : 1 1 : ?? ?? : 1 1 : ? ? : 1 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP ? Area of square = Area of circle ? x2 = ?r2? x/r = ?? = ? ? : 1
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 ?3 cm 3?3 cm 3 cm 9 cm ?3 cm 3?3 cm 3 cm 9 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
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. 558 Rs. 258 Rs. 458 Rs. 358 Rs. 558 Rs. 258 Rs. 458 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 hall 20 m long and 15 m broad is surrounded by a verandah of uniform width of 2.5 m. the cost of flooring the verandah at the rate of 3.50 per sq. meter is? Rs. 600 Rs. 700 Rs. 500 Rs. 800 Rs. 600 Rs. 700 Rs. 500 Rs. 800 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Area of verandah = [(25 x 20) -(20 x 15)] m2= 200 m2? Cost of flooring = Rs. (200 x 3.50)= Rs. 700
Area Problems Find the area of the trapezium, whose parallel sides are 12 cm and 10 cm, and distance between the parallel sides is 14 cm? 121 sq.com 154 sq.com 186 sq.com 164 sq.com 121 sq.com 154 sq.com 186 sq.com 164 sq.com ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Area of trapezium = 1/2 x (Sum of parallel sides) x (Distance between Parallel sides) = 1/2 x (12 + 10) x 14 = 22 x 14/2 = 22 x 7 = 154 sq. cm
EXAMIANS