Function to find the length of the direct common tangent
def lengtang ( r1 , r2 ) : NEW_LINE INDENT print ( " The ▁ length ▁ of ▁ the ▁ direct " , " common ▁ tangent ▁ is " , 2 * ( r1 * r2 ) ** ( 1 / 2 ) ) ; NEW_LINE DEDENT