4-1. Katya attached a square with a perimeter of 40 cm to a square with a perimeter of 100 cm as shown in the figure. What is the perimeter of the resulting figure in centimeters?

![](https://cdn.mathpix.com/cropped/2024_05_06_d9f67fd4a24dc8d44db8g-01.jpg?height=281&width=374&top_left_y=676&top_left_x=844)
Answer: 120.

Solution: If we add the perimeters of the two squares, we get $100+40=140$ cm. This is more than the perimeter of the resulting figure by twice the side of the smaller square. The side of the smaller square is $40: 4=10$ cm. Therefore, the answer is $140-20=120$ cm.