STEP 1: find height $ h $
To find height $ h $ use formula:
$$ \sin \left( \frac{ \beta }{ 2 } \right) = \dfrac{ h }{ d_2 } $$After substituting $ \beta = \frac{ 179 }{ 2 }^o $ and $ d_2 = 13542 $ we have:
$$ \sin \left( \frac{ 179^o }{ 2 } \right) = \dfrac{ h }{ 13542 } $$ $$ \sin( \frac{ 179 }{ 2 }^o ) = \dfrac{ h }{ 13542 } $$ $$ 1 = \dfrac{ h }{ 13542 } $$$$ h = 1 \cdot 13542 $$$$ h = 13541.4844 $$STEP 2: find incircle radius $ r $
To find incircle radius $ r $ use formula:
$$ h = 2 \cdot r $$After substituting $ h = 13541.4844 $ we have:
$$ 13541.4844 = 2 \cdot r $$ $$ r = \dfrac{ 13541.4844 }{ 2 } $$ $$ r \approx 6770.7422 $$