how do you fing the length of something when only given the perimeter?

Question

for ex. a rectangular garden has a perimeter of 240 ft. the lenght is 8 ft longer than its width. what is the length of the garden

Answer 1

You aren't only given the perimeter. You are also given the length as a function of the width.

L = w + 8
P = 2L + 2w

Plug L=w+8 into P:
P = 2(w + 8) + 2w
P = 2w + 16 + 2w
P = 4w + 16

P=240, so:
4w + 16 = 240
4w = 224
w = 56

L = (56) + 8
L = 64

Answer 2

You have given the length as a function of the width.

L = w + 8 [ here L=length & w=width]

we know,

P = 2L + 2W [here P=perimeter]

now putting L=w+8 into the above equation we get :

P = 2(w + 8) + 2w
P = 2w + 16 + 2w
P = 4w + 16

here perimeter P=240, so:

4w + 16 = 240
4w = 224
w = 56

L = 56 + 8
L = 64

so, the length of the garden will be 64 ft

Answer 3

The perimeter of something is the sum of the lengths of it's sides. For a rectangle this is L + L + W + W = 2(L + W)

L = W + 8
L + W = W + 8 + W = 2W +8

Perimeter = 240 = 2(L + W) = 2(2W + 8)
240 = 4W + 16
224 = 4W
so W = 56 and L = 64

Answer 4

p = 240

let w = width
l = w +8

so.. p = 2(w) + 2(w+8)
distribute: 240 = 2w + 2w + 16
add -16 to both sides: 240 - 16 = 4w
224 = 4w
w = 56

w = 56 ft
l = w+8 = 56 + 8 = 64 ft

^_^V

Answer 5

lets say...length is equal to x....and width is x - 8 (8 foot shorter)

2x + 2(x-8) = 240ft
(the lengths) + (the widths) = (perimeter)

multiply out the brackets
2x + 2x -16 = 240ft

add up
4x - 16 = 240ft

add 16 to both sides
4x = 256ft

divide by 4
x = 64ft

just use algebra :)