The formula for the area (A) of a rectangle is given by A = l * w, where l is the length and w is the width. We are asked to find the length and we are given the width (3 cm) and the area (123 cm2).
To find the length, we need to manipulate this formula to solve for l. So, divide both sides of the equation by w, this gives us: l = A / w.
We now substitute the given values into this equation:
l = 123 / 3
This simplifies to:
l = 41.0
So, the length of the rectangle is 41.0 cm.