Problem 02 - Simple Curve

$\cos \left( \dfrac{I}{2} \right) = \dfrac{R}{R + E}$
 

 

$\cos 18^\circ 15' = \dfrac{R}{R + 12.02}$

$R \cos 18^\circ 15' + 12.02 \cos 18^\circ 15' = R$

$R - R \cos 18^\circ 15' = 12.02 \cos 18^\circ 15'$

$R(1 - \cos 18^\circ 15') = 12.02 \cos 18^\circ 15'$

$R = \dfrac{12.02 \cos 18^\circ 15'}{1 - \cos 18^\circ 15'}$

$R = 226.94 \, \text{ m}$           [ C ]   answer