Easy Angles

Let the measure of $\angle{C}$ be $x$ . We know that the sum of a triangle's angles is $180^\circ$ . We also know that the first two angles sum up to $60^\circ$ . Therefore, the measure of $\angle{C}$ is $180^\circ-60^\circ=\boxed{120^\circ}$ .

The sum of the interior angles of a triangle is $180$ . So the missing angle is $180-20-40=\boxed{120}$

$180-(20+40)=180-60=120$

Hence the answer is $120$

The answer is $180 - (20 + 40) = \color{#69047E}{\boxed{120}}$ .

180-(20+40)=120

The sum of the internal angles of one triangle is 180°, the sum of A and B angles is 60°. 180-60=120. So the answer is 120°