Answer
$C= 50^\circ$
$a \approx4.91$
$b\approx4.52$
Work Step by Step
Step 1. Using the given conditions, we have $C=180-70-60=50^\circ$
Step 2. Using the Law of Sines, we have $\frac{a}{sin70^\circ}=\frac{b}{sin60^\circ}=\frac{4}{sin50^\circ}$
Step 3. Thus $a=\frac{4sin70^\circ}{sin50^\circ} \approx4.91$ and $b=\frac{4sin60^\circ}{sin50^\circ}\approx4.52$
