Question 975726
I'm assuming that the 2 cm radii are centered at the vertices. 
So then as you go across any leg you have 2 cm radius, diameter of larger circle, and then another 2 cm radius. 
{{{2+D+2=8}}}
{{{D=4}}} {{{cm}}}
The are length of the semicircles outside of the triangle would be three times half the circumference of the entire circle,
{{{L[1]=3*(1/2)pi*D}}}
{{{L[1]=6pi}}}
.
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The arc lengths of the internal circles are obtained using the arc length formula since each vertex is 60 degrees or {{{pi/3}}} radians.
{{{L[2]=3*2*(pi/3)}}}
{{{L[2]=2pi}}}
So the total length is,
{{{L=6pi+2pi}}}
{{{L=8pi}}}{{{cm}}}