Find the length of a side of an equilateral triangle that has the same perimeter as a square with a side length of 21 centimeters (cm) in centimeters (cm).
21 4 [OP_MUL] 3 [OP_DIV]
var_a = 21
var_b = 4
var_c = var_a * var_b
var_d = 3
var_e = var_c / var_d
print(int(var_e))