No, 60 is the third interior angle's mesure, not the exterior ∠3.
Step-by-step explanation:
Say that ∠1=∠A=50 and ∠2=∠B=70. The remote interior angles are the angles that are not touvhing the exterior angle. So ∠3 would be the the exterior angle to ∠C. ∠C=60 as the sum of the interior angles is 180.
The exterior angle is the angle formed by extending one of the triangle's sides. A straight line has the angle 180, so∠3=180-∠C=180-60=120.
