1.  If the area of the base of a right circular cone is 3850 cm2 and its height is 84 cm, then the curved surface area of the cone is :


10001 cm2
10010 cm2
10100 cm2
11000 cm2


Answer

 Option

πr2 = 3850. r2 = (3850 * 722) = 1225. r = 35. Now, r = 35 cm, h = 84 cm. So, l =(35)2 + (84)2 = 1225 + 7056 = 8281 = 91 cm. Curved surface area = (227 * 35 * 91) cm2 = 10010 cm2.

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2.  The sum of the radius of the base and the height of a solid cylinder is 37 metres. If the total surface area of the cylinder be 1628 sq. metres, its volume is :


3180 m3
4620 m3
5240 m3
None of these


Answer

 Option

(h + r) = 37 and 2πr(h + r) = 1628. 2πr * 37 = 1628 or r = (16282 * 37 * 722) = 7. So, r = 7 m and h = 30 m. Volume = (227 * 7 * 7 * 30) m3 = 4620 m3.

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3.  The volume of a right circular cylinder whose curved surface area is 2640 cm2 and circumference of its base is 66 cm, is :


3465 cm2
7720 cm2
13860 cm2
55440 cm2


Answer

 Option

2πr = 66; r = (66 * 12 * 722) = 212 cm. 2πrh2πr = (264066). h = 40 cm. Volume = (227 * 212 * 212 * 40) cm3 = 13860 cm3.

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4.  The surface area of a cube is 600 cm2. The length of its diagonal is :


103
102
102
103


Answer

 Option

6a2 = 600. a2 = 100 . a = 10. Diagonal =3a = 103 cm.

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5.  The curved surface area of a cylindrical pillar is 264 m2 and its volume is 924 m3. Find the ratio of its diameter to its height,


3 : 7
7 : 3
6 : 7
7 : 6


Answer

 Option

πr2h2πrh = 924264. r = (924264 * 2 ) = 7 m. And, 2πrh = 264. h = (264 * 722 * 12 * 17) = 6 m. Required ratio = h = 146 = 7 : 3.

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