If area of circle is equal to the area of square, then what is the relation between circumference (c) and perimeter (p) of the square?

The relationship is that the perimeter of the square is equal to the circumference of the circle multiplied by 1.13. Thus, p = 1.13 c. Here's how that's derived: the circle's area (πr²) is defined as being equal to the square's area (4s), where r is the circle's radius, and s is the square's side. So πr² = s², making s equal to r√π. The square's perimeter is 4s, or 4r√π. You would have to multiply the circumference (2πr) by (2/√π), or 1.13, to get the square's perimeter (4r√π). So the relationship of circumference to perimeter is p = 1.13 c. This is true only when the two areas are equal.