Each side of the square was increased by 1 cm. How much did the sum of the lengths of all sides of this square increase?

Let the side of the square be a cm.Then, if, in accordance with the condition of this problem, the side of the square was increased by 1 cm, then its new length will be equal to:
a + 1 (cm).
Now let’s determine what the sum of the lengths of the sides (that is, the perimeter) of the original square was equal to:
a + a + a + a = 4 * a (cm).
Then the sum of the lengths of the sides of the new square is:
4 * (a + 1) = 4 * a + 4 (cm).
T.o, the increase in the sum of the lengths of the sides was ultimately:
(4 * a + 4) – 4 * a = 4 (cm).
Answer: the perimeter has increased by 4 cm.