#### Answer

$A(w)=3w^{2}$
$w\gt 0$

#### Work Step by Step

We are told that the building has length three times the width ($l=3w$). Therefore, the area is:
Area=length*width=$l*w=3w*w=3w^2$
We should restrict $w\gt 0$, since the width can't be negative.

Published by
Brooks Cole

ISBN 10:
1305115546

ISBN 13:
978-1-30511-554-5

$A(w)=3w^{2}$
$w\gt 0$

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