Find the perimeter of the rectangle if its width is 3.42 dm and the length is 3.39 dm longer.

Width – 3.42 dm (by condition).
Length – 3.39 dm more than width (by condition).
We find the length of this rectangle – add the number 3.39 to the width, we get:
3.42 + 3.39 = 6.81 dm – the length of this rectangle.
The perimeter is the sum of all sides. Since the rectangle has two equal lengths of 6.81 dm and two identical widths of 3.42 dm, we get:
P = 6.81 + 6.81 + 3.42 + 3.42 = 19.2 dm – perimeter.
Answer: 19.2 dm.