geometry
posted by Anonymous .
the widthe width of a rectangle is 6 inches less than the length. the perimeter is 72 inches. find the lengtj and the width

first represent unknowns using variables:
let x = length of rectangle
let x6 = width of rectangle (according to first statement of problem)
now we set up equation,, since in the problem we are given the perimeter, we can use this to set up the equation,,
recall that perimeter of rectangle is
P = 2*(L+W)
where L is the length and W is the width
substituting,
72 = 2[ x + (x  6) ]
we can divide both sides by 2 (to cancel 2 on the right side):
72/2 = x + x  6
36 = 2x  6
42 = 2x
x = 21 inches (length)
x6 = 15 inches (width)
hope this helps~ :) 
cool