The surface area of hemisphere is given by:
[tex] Surface Area = 2 \pi r^{2} [/tex]
Where r is radius of hemisphere.
We are given diameter = 250 ft.
We know that radius = half of diameter.
Radius of dome = 1/2 (250) = 125 ft.
Now let us plug the value of radius in the formula,
[tex] Surface Area = 2 (3.14) (125)^{2} [/tex]
Surface Area of dome = 98125 square foot.