SOLUTION: Find the perimeter of the rectangle whose length is 40cm and a diagonal is 41cm.

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Question 814819: Find the perimeter of the rectangle
whose length is 40cm and a
diagonal is 41cm.
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Let y = size of unknown side.
40%5E2%2By%5E2=41%5E2, because the diagonal is the hypotenuse of the triangle with the legs, 40 and y.

y%5E2=41%5E2-40%5E2
y=sqrt%2841%5E2-40%5E2%29 which is simplifiable as
y=sqrt%28%2841-40%29%2841%2B40%29%29 --------- Do you recognize why?
y=sqrt%281%2A81%29
y=9

Solved for y is the main missing piece to finding the answer to the actual question, which I now leave for you to finish.