SOLUTION: i need help solving this problem: The length of a rectangle is 3 cm more than the width. The area is 70 cm^2. Find the dimentions of the rectangle.

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Question 435486: i need help solving this problem:
The length of a rectangle is 3 cm more than the width. The area is 70 cm^2. Find the dimentions of the rectangle.
Found 2 solutions by solver91311, MathLover1:
Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


Let represent the length. Then represets the width. The area of a rectangle is the length times the width, so:





Solve for . Discard the negative root (no such thing as negative length). Calculate

John

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Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

given:
The length of a rectangle: L is 3cm more than the width W.
The area is A=70+cm%5E2.
Find:
the dimentions of the rectangle
A=L%2AW
70cm%5E2=L%2AW.........L=W%2B3cm..substitute in 70+cm%5E2=L%2AW
70cm%5E2=%28W%2B3cm%29%2AW
70cm%5E2=W%5E2%2BW%2A3cm
W%5E2%2B3cm%2AW-70+cm%5E2=0..solve quadratic for W and use only positive root because W could not be negative
W+=+%28-%283cm%29+%2B-+sqrt%28+%283cm%29%5E2-4%2A1%2A%28-70+cm%5E2%29+%29%29%2F%282%2A1%29+
W+=+%28-3cm+%2B-+sqrt%28+9cm%5E2%2B280cm%5E2%29%29%2F2+
W+=+%28-3cm+%2B-+sqrt%28+289cm%5E2%29%29%2F2+
W+=+%28-3cm+%2B-+17cm%29%2F2+

W+=+%28-3cm+%2B+17cm%29+%29%29%2F2+
W+=+14cm%2F2+
W+=+7cm+......now find L
L=7cm%2B3cm
L=+10cm