SOLUTION: the length of a rectangle is 4 more than its width. the area of the rectangle is 45 square centimeters. whats is the length and width

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Question 955886: the length of a rectangle is 4 more than its width. the area of the rectangle is 45 square centimeters. whats is the length and width
Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!
the length of a rectangle L is 4 more than its width W.
L=W%2B4....eq.1
the area of the rectangle A is 45 square centimeters:
A=45cm%5E2
whats is the length and width
A=45cm%5E2
L%2AW=45cm%5E2 substitute L=W%2B4cm
%28W%2B4%29%2AW=45cm%5E2....solve for W
W%5E2%2B4W=45cm%5E2
W%5E2%2B4W-45cm%5E2=0

W+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
W+=+%28-4+%2B-+sqrt%28+4%5E2-4%2A1%2A%28-45cm%5E2%29+%29%29%2F%282%2A1%29+
W+=+%28-4+%2B-+sqrt%28+16%2B180cm%5E2%29%29%2F2
W+=+%28-4+%2B-+sqrt%28+196cm%5E2%29%29%2F2
W+=+%28-4+%2B-+14cm%29%2F2
solution: we need only positive solution for width
W+=+%28-4+%2B+14cm%29%2F2
W+=+10cm%2F2
W+=+5cm
then the length is
L=5cm%2B4cm
L=9cm

so, the length is highlight%289cm%29 and the width is highlight%285cm%29