Answer:
Step-by-step explanation:
using sin formula
let third angle=α
[tex]\frac{sin~\alpha }{7.9} =\frac{sin 18}{8.4} \\sin \alpha=\frac{7.9}{8.4} \times sin~18\\\alpha=sin^{-1} (\frac{7.9}{8.4} \times sin18)\\\approx 16 ^\circ 54'\\\theta=180-(18+16^\circ 54')\\=180-34^\circ54'\\=145^\circ 06'[/tex]
