the side of a cube is 7cm .the biggest sphere has been cut from the cube the radius of the sphere is
 

we know that if a solid is transformed into any other solid, its volume is always same.

vol. of cube= vol. of sphere

7×7×7 = 4/3×22/7×r×r

343 = 4.19×r×r

r×r =343/4.19

r×r = 81.86

r = √81.86

:) :) :)