We have solid sphere whose radius from it's center is 7 unit. Then we cut very small circular area on the surface of sphere.
Each outer point of this small circular area meet at the center of the sphere and formed a cone. Whose slant hight and radius from it's center is almost same because circular area is very small just like a point circle.

This base area of formed cone is A₁ and it's volume is equal to volume of cone = 1/3(base area x height)
= 1/3(A₁ x R)
And like this we cut many more cones and sum of volume of all these cones is equal to volume of sphere.
The base area of these cone are A₁ , A₂ , A₃ ......., A_n
Total surface area of sphere =(A₁ + A₂ + A₃ +....... + A_n) = A(LET)

Sum of volume of all the cones = volume of sphere
1/3 x A₁ R +1/3 x A₂ R +.........+ 1/3 x A_n = 4/3 x (22/7)R³
1/3 x R(A₁ + A₂ + A₃ +.......+ A_n) = 4/3(22/7)R³
1/3 x R x (A) = 4/3 x (22/7)R³
A = 4/3 x (22/7)R³ x 3/R
A = 4(22/7)R²
So surface area of sphere = 4(22/7)7² = 616 unit area.