Answer
1355 m
Work Step by Step
Use law of cosines, we have
$c^{2}=a^{2}+b^{2}-2ab cos \theta$
As per question:
$|AB|^{2}=|AC|^{2}+|BC|^{2}-2|AC||BC| cos 103^{\circ}$
$|AB|^{2}=820^{2}+910^{2}-2(820)(910) cos 103^{\circ}$
$|AB|=\sqrt {820^{2}+910^{2}-2(820)(910) cos 103^{\circ}}$
$|AB|=1355$ m
