Solve. A lamp shade has the geometric form shown below. The total surface area of a lamp shade with slant height s and top and bottom base radii of r2 and r1, respectively, is given by the expression
Factor this expression. 
A. ?(r1 + r2)(r1 + r2 + sr1r2)
B. ?r1(r1 + + sr1 + sr2)
C. ?(r12 + r22 + sr1 + sr2)
D. ?(r1 + r2)(r1 + r2 + s)
Answer: C
Mathematics