Question 540676
the length of a rectangle is 3 less than twice the width. if the perimeter is 72cm, what is the lenght of the rectangle? 
:
Write an equation for each statement:
"the length of a rectangle is 3 less than twice the width. "
L = 2W - 3
:
"the perimeter is 72cm,"
2L + 2W = 72
This eq can be simplified, divide thru by 2
L + W = 36
:
From the 1st statement, replace L with (2W-3) in the above equation
(2W-3) + W = 36
add 3 to both sides
2W - 3 + 3 + W = 36 + 3
3W = 39
divide both sides by 3
W = 13 is the width
then
L = 2W - 3
L = 2(13) - 3
L = 26 - 3
L = 23 is length
:
:
Check this in the perimeter equation
2(23) + 2(13) =
46 + 26 = 72