Each side of square frame can be 10 inches long.
Step-by-step explanation:
Before delving into the problem we need to know some facts about “Square”
As given in the question the picture frame is square with 40 inches perimeter
Thus 4s=40 inches ∴where s= measure of the square’s side
∴ s=10 inches ⇒ s= measure of the square’s side
∴ hence the measure of the square’s side frame is 10 inches