Answer:
B; C; A; B
Step-by-step explanation:
So, let's go through each of the choices.
So we know that one of the angles is 60 degrees.
I) The triangle is scalene.
This might be true. Since there are 180 degrees in a triangle, and we know 60, that leaves 120 degrees. Anything two combinations of different values that add up to 120 will make the triangle scalene. However, if the two values are the same (e.g. 60;60), they it's not scalene. Thus, this might be true.
II) The other two angles add up to 120.
This must be true. The interior angles sum of a triangle is 180. Since we already know one is 60, then the other two must add up to be 180-60 or 120.
III) The other two angles are obtuse.
This cannot be true. We know that there is only 120 degrees left in the triangle. Obtuse angles are greater than 90 degrees.
Therefore, if we subtract the minimum: 120-90, we will get at most 30 left. This is not enough for another obtuse angle. The most we can have is one obtuse angle and two acute angles.
IV) The triangle is right-angled.
This might be true. Since there are 120 degrees left, the other two degrees may be 90 and 30, given us 30-60-90. This, however, doesn't have to be it. So, this statement may be true.
