What is the surface area of the right prism? 972 in2 540 in2 486 in2 648 in2

2 surfaces are 6 in by 9 in, meaning that their combined area is 2(54 in^2).
2 surfaces are 6 in by 18 in; combined area is 2(108 in^2).
2 surfaces are 9 in by 18 in; combined area is 2(162 in^2).

Add up these areas:  A = 2(54+108+162) in^2 = 648 in^2 (answer)

The correct answer is: b