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? 7 cm 5 cm 4 cm 6 cm 7 cm 5 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 radius of the wheel of a vehicle is 70 cm. The wheel makes 10 revolutions in 5 seconds. The speed of the vehicle is? 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. 31.68 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 The area of circle inscribed in an equilateral triangle is 462 cm . The perimeter of the triangle is? 72.6 cms 126 cms 168 cms 42 ? 3 cms 72.6 cms 126 cms 168 cms 42 ? 3 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 What is the least number of squares tiles required to pave the floor of a room 15 m 17 cm long and 9 m 2 cm broad? 814 844 840 820 814 844 840 820 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Length of largest tile = H.C.F. of 1517 cm and 902 cm = 41 cm. Area of each tile = (41 x 41) cm2. ∴ Required number of tiles = ❨ 1517 x 902 ❩ = 814
Area Problems The base of a triangular field is three times its altitude. If the cost of cultivating the field at Rs. 24.68 per hectare be Rs. 333.18, find its base and height. B=500;H=900 B=900;H=300 B=600;H=700 B=300;H=900 B=500;H=900 B=900;H=300 B=600;H=700 B=300;H=900 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Area of the field = Total cost/rate = (333.18/25.6) = 13.5 hectares 13 . 5 * 10000 m 2 = 135000 m 2 Let altitude = x metres and base = 3x metres.Then, 1 2 * 3 x * x = 135000 ? x 2 = 90000 ? x = 300 Base = 900 m and Altitude = 300 m.
Area Problems If the radius of a circle is increased by 6%, find the percentage increase in its area. 15% 12.36% 8.39% 17% 15% 12.36% 8.39% 17% ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Given that, a = 6 According to the formula,Percentage increase in area= 2a + [a2/100]%= 2 x 6 + [36/100]%= (12 + 0.36)%= 12.36%
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