SOLUTION: The perimeter of a rectangular plot of land is 70 meters. The length of a diagonal is 25 meters. calculate the length and width of the plot

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Question 1096569: The perimeter of a rectangular plot of land is 70 meters. The length of a diagonal is 25 meters. calculate the length and width of the plot
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
The perimeter of a rectangular plot of land is 70 meters.
2L + 2w = 70
simplify, divide by 2
L + w = 35
L = -w + 35, we can use this form for substitution
:
The length of a diagonal is 25 meters.
L%5E2+%2B+w%5E2+=+25%5E2
L%5E2+%2B+w%5E2+=+625
Replace L with (-w+35)
%28-w%2B35%29%5E2+%2B+w%5E2+=+625
FOIL (-w+35)(-w+35)
w%5E2+-+35w+-+35w+%2B+1225+%2B+w%5E2+=+625
arrange as a quadratic equation
2w%5E2+-+70w+%2B+1225+-+625+=+0
2w%5E2+-+70w+%2B+600+=+0
simplify divide by 2
w%5E2+-+35w+%2B+300+=+0
You can use the quadratic formula; a=1;b=-35;c=300, but this will factor to:
(w-15)(w-20) = 0
two solution
w = 15 m is the width, then the length 35 - 15 = 20 m
or
w = 20 m is the width, then the length is 15 m
:
calculate the length and width of the plot: 20 by 15
:
;
:
Check this solution by finding the diagonal
d = sqrt%2820%5E2+%2B+15%5E2%29