SOLUTION: Hi and thanks for answering my question! One pair of opposite sides of a rectangle increased in length by 25%. By what percent must the other pair of sides decrease if the area

Algebra ->  Rectangles -> SOLUTION: Hi and thanks for answering my question! One pair of opposite sides of a rectangle increased in length by 25%. By what percent must the other pair of sides decrease if the area       Log On


   

Question 974997: Hi and thanks for answering my question!
One pair of opposite sides of a rectangle increased in length by 25%. By what percent must the other pair of sides decrease if the area of the rectangle remains the same?
Please include a brief explanation too, thank you!
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Dimensions x and y of the original rectangle.
xy=A for area.

%285%2F4%29x%2Ak%2Ay=A, simpler to think in factors, first.

k%285%2F4%29xy=A
k=%284%2F5%29%281%2F%28xy%29%29A
k=%284%2F5%29%28A%2FA%29
k=4%2F5----------------a decrease in the original y dimension of 20%.