The length of a rectangle is 4cm langer than the width. the perimeter is 80cm. what is the length and the width?

Let us assume the width of the rectangle = x cm
Then
The length of the rectangle = (x + 4) cm
It is already given that
Perimeter of the rectangle = 80 cm
Now we also know the formula for perimeter of a rectangle
Perimeter = 2 ( length + width)
80 = 2 (x + 4 + x)
80 = 2 (2x + 4)
80/2 = 2x + 4
40 = 2x + 4
Dividing both sides by 2 we get
20 = x + 2
20 -2 = x
x = 18
Then
Width of the rectangle = 18 cm
Length of the rectangle = (18 + 4) cm
                                     = 22 cm
So the rectangle has a length of 22 cm and a width of 18 cm.