Explanation:

The height of the cone = 28 cm
Surface area of the sphere= 616 cm³
We know that the surface area of the sphere = 4∏r²
=4∏r² = 616
= r²= 49
= r =7
Radius of the sphere = 7 cm
Let R be the radius of the cone
Volume of the cone = (1/3)∏r²h
= (1/3)∏r²28………………….(i)
Volume of the sphere= (4/3)∏r³
= (4/3)∏7³ …………………..(ii)
Comparing equation (i) and (ii)
R²= 49
R=7
Diameter of the cone = 7*2 = 14 cm
The diameter of the base of the cone is 14 cm