Find the percent (1.6) of the unpaid balance (1250)
1250 x .016 = 20
Add the answer (20) to the unpaid balance (1250)
Answer is $1270
The formula for surface area is SA=4pi(radius)^2
This means that 4SA=4pi(2r)^2
because 2^2=4
so multiply the first ball's surface area by 4
the answer is c
