Attached the solution and work.
.12 * $355 = $42.60. That is his discount.
Answer:
972cm^3
Step-by-step explanation:
use the formula for a rectangular prism base x height x length but then divid by two because it is a triangular prism.
multiply 18 x 12 x 9 then divide by 2
Can you put an image of the triangle???