If the length of a rectangle is "l” and width is "b”, then perimeter of the rectangle is:
l+b
2l+b
l+2b
2(l+b)
The perimeter of a rectangle is equal to 2 × (length+breadth) = 2(l+b)
If the perimeter of a rectangle is 23 cm and its width is 4 cm, then find the length of the rectangle.