A rectangle with sides 3cm and 4cm was cut out of a square with a side of 10cm. Find the perimeter of the remainder.

In this case, when performing this task, it is necessary to make a drawing, so we will clearly see where and where the sides come from. A square with sides 10 has a perimeter of 40, a piece with dimensions 3 and 4 was cut off from it. The area has changed, but the perimeter has not changed at all, so the perimeter of the remaining part will be 40.