Area Problems If the diagonal of a rectangle is 17cm long and its perimeter is 46 cm. Find the area of the rectangle. 140 120 130 110 140 120 130 110 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP let length = x and breadth = y then 2(x+y) = 46 => x+y = 23 x²+y² = 17² = 289 now (x+y)² = 23² => x²+y²+2xy= 529 => 289+ 2xy = 529 => xy = 120 area = xy = 120 sq.cm
Area Problems The sides of a triangular board are 13 meters, 14 meters and 15 meters. The cost of paining it at the rate of Rs. 8.75 per m 2 is? Rs. 688.80 Rs. 735 Rs. 722.50 Rs. 730.80 Rs. 688.80 Rs. 735 Rs. 722.50 Rs. 730.80 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP s = (13 + 14 + 15 ) / 2 = 21, s-a = 8 , s-b = 7, s-c= 6? Area to be painted = ? [s(s-a) (s-b) (s-c)]=? [21 x 8 x 7 x 6] m2= 84 m2? Cost of painting = Rs. (84 x 8.75) = Rs. 735
Area Problems The altitude of an equilateral triangle of side 2 ? 3 cm is? ? 3/4 1/2 cm ? 3/2 cm 3 cm ? 3/4 1/2 cm ? 3/2 cm 3 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP ? 1/2 x 2 ? x h = ?3/4 x (2 ?3)2? h = 3 cm.
Area Problems The perimeter of a rectangle having area equal to 144 cm 2 and sides in the ratio 4 : 9 is 56 cm 64 cm 60 cm 52 cm 56 cm 64 cm 60 cm 52 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let l = 4k and b = 9kArea of rectangle = l x b144 = 4k x 9k ? k2 = 144/36 ? k2 = 4? k = 2? l = 8 cm and b = 18 cmPerimeter of rectangle = 2(l + b)= 2(8 + 18)= 2 x 26= 52 cm
Area Problems The difference between the circumference and the radius of a circle is 37 cm. The area of a circle is? 259 sq. cm 111 sq. cm 148 sq. cm 154 sq. cm 259 sq. cm 111 sq. cm 148 sq. cm 154 sq. cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP ? 2?r - r = 37? [(2 x 22/7) -1]r= 37? 37r / 7= 37? r = 7 So, area of the circle =(22/7) x 7 x 7 cm2= 154 cm2
Area Problems A rectangular field is to be fenced on three sides leaving a side of 20 feet uncovered. If the area of the field is 680 sq. feet, how many feet of fencing will be required? 34 40 88 68 34 40 88 68 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP We have: l = 20 ft and lb = 680 sq. ft. So, b = 34 ft. ∴ Length of fencing = (l + 2b) = (20 + 68) ft = 88 ft