She underestimated by 60 cents. To get this answer all you need to do is multiply 1 dollar times 12 which is $12 and then multiply $.30 by 12 and that gives you $3.60. Then you add the $12 to the $3.60 and that gives you $15.60 which is 60 cents over the estimation.
2l + 2w = 16
2(l+ w) = 16 Divide both sides by 2
l + w = 16/2
l + w = 8
So for example the length l could be 5 and the width could be 3.
Length could be 5.
21.325 is the correct answer
