Area Problems In a triangle ABC, BC = 5 cm AC = 12 cm and AB = 13 cm. The length of a altitude drawn from B on AC is? 5 cm 7 cm 4 cm 6 cm 5 cm 7 cm 4 cm 6 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP ? s= (13 + 5 + 12) / 2 cm = 15cms-a = 2 cm, s-b = 10 cm and s-c = 3 cm ? Area = ? (15 x 2 x 10 x 3 ) cm2= 30 cm2? (12 x h) / 2 = 30 ? h = 5 cm
Area Problems The perimeter of an isosceles triangle is equal to 14 cm . The lateral side is to the base in the ratio 5 : 4 the area of the triangle is? 2?21 cm2 ?212 1/2?21 cm2 3/2?21 cm2 2?21 cm2 ?212 1/2?21 cm2 3/2?21 cm2 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let lateral side = (5y) cm and base = (4y) cm ? perimeter = 5y + 5y + 4y = 14 ?y = 1So, the sides are 5 cm , 5 cm and 4 cm Now s= 1/2 (5 + 5 + 4) cm = 7 cm (s-a) = 2 cm (s-b) = 2 cm and (s-c) = 3 cm? Required Area = ? (7 x 2 x 2 x 3) cm2=2?21 cm2
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. 722.50 Rs. 688.80 Rs. 730.80 Rs. 735 Rs. 722.50 Rs. 688.80 Rs. 730.80 Rs. 735 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 If the diagonal of a square is double, how does the area of the square change? Becomes three fold Becomes two fold None of these Becomes four fold Becomes three fold Becomes two fold None of these Becomes four fold ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Ratio of the areas = area of original square / area of new square = [ d2 / 2 ] / [ (2d)2 / 2 ] = 1/4? New area becomes 4 fold.
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
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