Question 1180635


<a href="https://ibb.co/4d8Fd2T"><img src="https://i.ibb.co/4d8Fd2T/pulleys.png" alt="pulleys" border="0"></a>

<a href="https://ibb.co/W25xCb0"><img src="https://i.ibb.co/W25xCb0/formula.png" alt="formula" border="0"></a>


{{{L=2C+(pi/2)(D+d)+(D-d)^2/4C}}}

given:
{{{C=30 }}}
{{{r=6}}}->{{{d=12}}}
{{{R=21}}}->{{{D=42}}}


{{{L=2*30+(pi/2)(42+12)+(42-12)^2/(4*30)}}}
{{{L=60+84.78+7.5}}}
{{{L=152.3cm}}}