If S1 and S2 be the whole surface of a sphere and the curved surface of the circumscribed cylinder, then S1 is equal to
a)S2, b)2S2 c)(1/2)S2 d)(2/3)S2
The length of the sides of a triangle are in integers and its area
>is also an integer. One side is 21 cm and the perimeter is 48 cm,
>then the length of the shortest side is :