Did she make an error? Amelie wants to decorate the outside of the box but not
the bottom. It is a 5 in. by 3 in. by 2 rectangular prism. If
the beads that she is using cost $0.25 per square inch,
how much will she pay for the beads? Her work is shown.
Yes, she should have only added the area of five of
the six faces.
Yes, she did not use the correct area formula for a
rectangle
Ol Yes, she calculated the cost incorrectly.
surface area = 15 + 15 + 6 + 6 + 10 + 10 = 62 in.
cost = 0.25(62) = $15.50
No, she didn't make any errors.