aREA A ND pERIMETER

[wrb]

gIVE ME THE DIMENSIONS (LENGTH AND WIDTH) OF A RECTANGLE WIITH THE AREA = 36 AND PERIMETER=30
pLEASE EXPLAIN HOW YOU GOT YOUR ANSWER AND WITH AN EXAMPLE

 

[arthur ohlsten]

LW=36
L=36/W
=================================
2L+2W=30
L+W=15 substitute for L,36/W
36/W +W=15 multiply both sides by W
36+w^2=15W
W^2-15W+36=0

factors of 36 are 1,36...2,18...3,12...4,9...6,6
we want a set whose sum is 15....3,12 does it
w^2-15W+36=0 factor
[W-3][W-12]=0
W=3 or W=12 substitute into L=36/W
L=12 or L=3
W=3,L=12 or W=12 L=3 answer
Arthur