Question 830609
I'm assuming you're building a perimeter fence around the rectangle.  For that, you'll need 2 pieces of the length and 2 pieces of the width (P=2L+2L).
Your length is 4 yards, which is 12 feet (1 yard = 3 feet).
Your width is 3 yards, which is 9 feet (3*3=9)
So, to build a perimeter fence, you'll need:
(12*2) + (9*2)
24 + 18 = 42
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No, you do not have enough fencing.
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I suspect a lot of students will get this wrong because they'll fail to convert yards to feet.