In Example 4, change 2.0 mm to 3.0 mm, and then solve.

Data from Example 4

The length of a rectangular computer chip is 2.0 mm longer than its width. Find the dimensions of the chip if its perimeter is 26.4 mm.

Because the dimensions, the length and the width, are required, let w = the width of the chip. Because the length is 2.0 mm more than the width, we know that w + 2.0 = the length of the chip. See Fig. 2.60.

Because the perimeter of a rectangle is twice the length plus twice the width, we have the equation

2(w + 2.0) + 2w = 26.4

because the perimeter is given as 26.4 mm. This is the equation we need. Solving this equation, we have

Therefore, the length is 7.6 mm and the width is 5.6 mm. These values check with the statements of the original problem.

2w+ 4.0+ 2w = 26.4 4w = 22.4 w = 5.6 mm