To solve this problem you must apply the proccedure shown below:
1. Clear the radius from the formula for the circumference of a circle and substitute values, as following:

2. Substitute the radius calculated into the formula for calculate the surface area of the sphere:

The answer is: 
Answer:
C≈157.08in
Step-by-step explanation:
C=2πr=2·π·25≈157.07963in
D is the bast answer for this question, but, the equation should be (78-54)/3=p.
X= 130 degrees since 180 is the total minus 50 from above