Function to find the fourth circle 's when three radius are given
def findRadius ( r1 , r2 , r3 ) : NEW_LINE INDENT r4 = ( r1 * r2 * r3 ) / ( r1 * r2 + r2 * r3 + r1 * r3 + 2.0 * sqrt ( r1 * r2 * r3 * ( r1 + r2 + r3 ) ) ) NEW_LINE return r4 NEW_LINE DEDENT