Problem $5\mathrm{.}1\mathrm{.}9($figure from $5\mathrm{.}1\mathrm{.}3)$

$5\mathrm{.}1\mathrm{.}9.$ For E$5\mathrm{.}1\mathrm{.}3,$ find

a$.$ the magnitude of $r_2$

b$.($the angle between $r_2$ and the $1\mathrm{.}2-kN$ tension force$)$

c$.$ the magnitude of the moment $M$ for a moment center

at the origin of the coordinate system shown