θ → ( 5 , − 12 ) {\displaystyle \theta \rightarrow (5,-12)}
θ → x = 5 , y = − 12 , r = ? ( 5 ) 2 + ( − 12 ) 2 = r 2 {\displaystyle {\begin{aligned}\theta \rightarrow x=5,\,y=-12,\,r=?\\(5)^{2}+(-12)^{2}=r^{2}\end{aligned}}}
