1. A right circular conical structure stands on a circular base of 21m diameter and is 14m in height. The total cost of colour washing for its curved surface at Rs. 6 per sq. m. is (Take ? = 22/7 )
4. Two circles touch each other externally. The distance between their centres is 7 cm. If the radius of one circle is 4 cm, then the radius of the other circle will be
5. An arc of 30° in one circle is double an arc in a second circle, the radius of which is three times the radius of the first. Then the angles subtended by the arc of the second circle at its centre is
7. Radius of cross section of a solid right circular cylindrical rod is 3.2 dm. The rod is melted and 44 equal solid cubes of side 8 cm are formed. The length of the rod is (Take ? = 22/7)
8. If the volumes of two right circular cones are in the ratio 1:4 and their diameters of bases in the ratio 4:5, then their heights will be in the ratio: