When two straight lines intersect, the angles opposite each other are equal, and the sum of all four angles at that point will be 360° (because there is a full circle's worth of angles around the point of intersection).
Given that one angle is 30°, the angle directly opposite to it must also be 30° because they are vertical angles, and vertical angles are equal.
Since the lines are straight, each pair of adjacent angles must sum up to 180° because they form a straight line. Since we already have one angle that is 30°, the adjacent angle to it must be 180° - 30° = 150° to complete the straight line. This 150° angle is opposite the remaining angle, which must therefore also be 150°.
So, the set of all four angles will be:
- The given angle: 30°
- The angle opposite the given one: also 30°
- The angle adjacent to the given one: 150°
- The angle opposite to the 150° one (also adjacent to the given one): also 150°
Hence, the correct answer is:
C. 30°, 150°, 150°
