1. ## Laws Of Sine

i have one quick question...

a problem gives us that:

A= 60 degrees, a=9, c = 10...
my only concern is that if the remaining two angles are also 60...

2. you can't just assume that. you can assume though that the other two angles will add up to 120 degrees though.

Use Law of Sines:

$\frac{Sin 60}{9}=\frac{Sin C}{10}$

$\frac{\frac{\sqrt{3}}{2}}{9}=\frac{Sin C}{10}$

Criss-Cross multiply: $9SinC = \frac{10\sqrt{3}}{2} = 5\sqrt{3}$

So: $SinC = \frac{5\sqrt{3}}{9}$

We need the angle, so we use inverse Sin ( $Sin^{ - 1}$).

$C = Sin^{ - 1} (\frac{5\sqrt{3}}{9}) \approx 74.21^o$

The other angle is approximately $120 - 74.21 = 45.79^o$