The surface area of a sphere is

where r is the radius;
The circumference is

so that

using this value we can evaluate the surface area of 1 ball as:

For 100 ball you get:
Answer:
r-9
Step-by-step explanation:
Isolate the variable by dividing each side by factors that don't contain the variable
brainleist?
Move all terms not containing U to the right side of the equation.
Exact Form:
U = 1/2
Decimal Form:
U = 0.5