The numerical value of the area of a square is 3 times it's perimeter. What is the length of its side?

Let the length be x

Area = x²

Perimeter = 4x

Area of a square is 3 times its perimeter

⇒ x² = 3 (4x)

x² = 3 (4x)

x² = 12x

x² - 12x = 0

x (x - 12) = 0

x = 0 or x = 12

Since x cannot be zero, x = 12

Answer: The length is 12 units.