SOLUTION: The perimeter of a rectangle is 146 inches. The length is 7 inches shorter than three times the width. Find the length.

Algebra ->  Rectangles -> SOLUTION: The perimeter of a rectangle is 146 inches. The length is 7 inches shorter than three times the width. Find the length.      Log On


   



Question 1063302: The perimeter of a rectangle is 146 inches. The length is 7 inches shorter than three
times the width. Find the length.

Found 3 solutions by addingup, josgarithmetic, MathTherapy:
Answer by addingup(3677) About Me  (Show Source):
You can put this solution on YOUR website!
perimeter = 2*width + 2*length, or the long way: width + width + length + length. In other words, all around the edge of the rectangle, what we call the perimeter.
-----------------------------
Length = 3W-7
So now we have:
2W+2(3W-7) = 146 distribute the 2 over the "stuff" in the parenthesis (Distributive Property of Multiplication):
2W+6W-14 = 146
8W = 160
W = 20
------------------------------------
Check:
2(20)+2(3*(20)-7)
40+106 = 146 Correct
:
John

Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
w Width
L length
system%282w%2B2L=146%2CL=-7%2B3w%29

system%28w%2BL=73%2CL=3w-7%29

w%2B3w-7=73

4w=80

system%28w=20%2CL=3%2A20-7=highlight%2853%29%29

Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!

The perimeter of a rectangle is 146 inches. The length is 7 inches shorter than three times the width. Find the length.
Let length be L and width, W
Then: 2(L + W) = 146______2(L + W) = 2(73)_____L + W = 73______W = 73 - L ------ eq (i)
Also, L = 3W - 7 ------- eq (ii)
L = 3(73 - L) - 7 ------ Substituting 73 - L for W in eq (ii)
L = 219 - 3L - 7
L + 3L = 219 - 7
4L = 212
L, or length = highlight_green%28matrix%281%2C4%2C+212%2F4%2C+or%2C+53%2C+inches%29%29