Constants $($in mm$)$

$a_1=860$

$b_1=940$

$a_2=420$

$a_3=1240$

$b_3=1160$

$c_3=350$

$a_4=620$

$a_5=710$

Variables

${}_{12}\frac{\text{:}}{{?}_A{?}_0}A$

${}_{13}\frac{\text{:}}{{?}_A}B$

${}_{14}\frac{\text{:}}{{?}_B{?}_0}B$

${}_{15}\frac{\text{:}}{{?}_C}D(not$ shown$)$

$s_{16}$:$B{B}_{0}D(not$ shown$)$

where is s$16$ and teta$15$ angles $?$