Question

I really need help...

Answer 1

The sum of interior angles in a triangle is 180°

If an angle is 120°, then the sum of the other angles is
180° - 120°
= 60°

First, second, and third options are less than 60°. So the three choices are possible angle to the triangle.

The fourth option isn't possible for the triangle. So the answer of the question is fourth option (73°)

Answer 2

It could not be 73º because if you add that to 120 then it will be more than 180 degrees, which is the total number of degrees in a triangle. Hope this helps!