Question

Calculate the value of angle A and C of ∆ ABC. Where b=1435cm, a= 782cm and B= 115.6°.​

Answer 1

The Law of Sines says

`(\sin A)/(a) = (\sin B)/(b) = (\sin C)/(c)`

`\sin A = \frac a b \sin B`

`A = \arcsin( (782)/(1435) \sin 115.6 ) = 29.44^\circ`

We don't have to worry about the obtuse supplement because a triangle can only have one obtuse angle, and that's B.

`C = 180 - 115.6 - 29.44 = 34.96^\circ`

Answer: A=29.44°, C=34.96°