There is a rectangular sheet of iron, 96 cm long and 80 cm wide How many centimeters is the longest side of a square?

There is a rectangular sheet of iron, 96 cm long and 80 cm wide How many centimeters is the longest side of a square?

Is to find the greatest common factor of 96 and 80
The greatest common factor of 96 and 80 is 16
The longest side of a square is 16 cm