Answer:
Step-by-step explanation:
If you don't consider how the wood might be cut, or how the tray might be assembled, you can look only at the area requirements.
A tray that is 10.5 inches square will have an area of ...
(10.5 in)^2 = 110.25 in^2
That base will have a perimeter that is 4×10.5 in = 42 in. If the perimeter piece(s) are 2 inches high, the area of the sides of the tray will be ...
(42 in)(2 in) = 84 in^2
Then the total area of wood required for the proposed tray is ...
110.25 in^2 +84 in^2 = 194.25 in^2
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The area of the wood Stephan has is ...
A = LW = (18 in)(12 in) = 216 in^2 . . . . . . more than required
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Stephan does have enough wood to make the tray, because he has 216 square inches, which is more than he needs to make the tray, 194.25 square inches.
