What is the surface area of sphere with radius 13 ft

Sum is 17 and their difference is 3

The ivring berlin learning center would like a possible net profit of $650,000 on its new resource manual it sells to schools. the fixed costs for producing the manual are $780,000 and the variable cost per package is $19.85. if the estimated unit sales are 1,250,000 units, what selling price unit should the ivring berlin learning center try?

What is the area of the shaded sector?