The central angle and radius of a sector of a circular disc are `180^(@)` and 21 cm respectively. If the edges of the sector are joined together to make a hollow cone, then find the radius of the cone.

The external radius and the length of a hollow wooden log are 16 cm and 13 cm respectively. If its thickness is 4 cm then find its T.S.A.

The radii of the bases of two right circular solid cones of same height are r_(1) and r_(2) respectively. The cones are melted and recast into a solid sphere of Radius ''R'' show the height of the cone is given by h=(4R^(3))/(r_(1)^(2)+r_(2)^(2)

Three metallic spheres of radii 6 cm, 8 cm and 10 cm respectively are melted together to form a single solid sphere. Find the radius ofthe resulting sphere.

A metallic sheet in the form of a sector of a circle of radius 21 cm has central angle of 216^(@) . The sector is made into a cone by bringing the bounding radii together. Find the volume of the cone formed.

A chord of a circle of radius 6cm is making an angle 60 ^(@) at the centre.Find the length of the chord.

The volume of a solid right circular cone is 11088 cm^(3) . If its height is 24 cm then find the radius of the cone.

Find the volume of a right-circular cone of base radius r and height h.