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? 6 cm 5 cm 4 cm 7 cm 6 cm 5 cm 4 cm 7 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 A tank is 25 m long, 12 m wide and 6 m deep. The cost of plastering its walls and bottom at 75 paise per sq. m, is: Rs. 558 Rs. 568 Rs. 458 Rs. 456 Rs. 558 Rs. 568 Rs. 458 Rs. 456 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Area to be plastered = [2(l + b) x h] + (l x b) = {[2(25 + 12) x 6] + (25 x 12)} m2 = (444 + 300) m2 = 744 m2. ∴ Cost of plastering = Rs. ❨ 744 x 75 ❩ = Rs. 558
Area Problems The area of circle inscribed in an equilateral triangle is 462 cm . The perimeter of the triangle is? 168 cms 42 ? 3 cms 72.6 cms 126 cms 168 cms 42 ? 3 cms 72.6 cms 126 cms ANSWER EXPLANATION DOWNLOAD EXAMIANS APP ? 22/7 x r2 = 462? r2 = (462 x 7) /22 = 147? r = 7?3 cm ? Height of the triangle = 3r = 21?3 cmNow, ? a2 = a2/4 + (3r)2? 3a2/4 = (21?3)2? a2 = (1323 x 4)/3? a = 21x 2 = 42 cm? Perimeter = 3a = 3 x 42=126 cm
Area Problems The altitude of an equilateral triangle of side 2 ? 3 cm is? 3 cm ? 3/4 1/2 cm ? 3/2 cm 3 cm ? 3/4 1/2 cm ? 3/2 cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP ? 1/2 x 2 ? x h = ?3/4 x (2 ?3)2? h = 3 cm.
Area Problems If the length of diagonal AC of a square ABCD is 5.2 cm then area of the square ABCD is? 12.62 sq.cm 13.52 sq.cm 10 sq.cm 15.12 sq.cm 12.62 sq.cm 13.52 sq.cm 10 sq.cm 15.12 sq.cm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Area = 1/2 x (Diagonal)2= (1/2) x 5.2 x 5.2 cm2= 13.52 cm2
Area Problems The area of a rectangle, 144 m long is the same as that of a square having a side 84 m long. The width of the rectangle is? 7 m 49 m Cannot be determined 14 m 7 m 49 m Cannot be determined 14 m ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Area of the square = (84 + 84) m2Area of the rectangle = (144 x width) m2From question both area would be same,? Width = (84 x 84) / 144 m = 49 m
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