Question 701136
volume of a cone= V= (1/3)pi*r^2*h
here
r= radius of the base of cone
h= perpendicular distance between base and vertex of cone  
pi=3.14159
we know diameter of a cone = 6 
hence radius =r=6/2=3

given distance between the vertices of the cones = 6 =2h
 hence  h= 6/2 = 3

since two congruent cones combined entire volume of the solid should be 2V

hence required volume=  2*(1/3)pi*r^2*h = 2*(1/3)pi*3^2*3  = 56.54866776