How can you check if a segment is an angle bisector of a triangle?
Answer
Check if the areas of the two triangles the segment forms are equal.
Check if measures of the two angles the segment divides the vertex angle into are the same.
Check if the segment meets a side of the triangle at a right angle and divides the side into two congruent parts.
Check if the segment meets a side of the triangle at a right angle and divides the vertex angle into two congruent angles.

Question

How can you check if a segment is an angle bisector of a triangle?
Answer
		Check if the areas of the two triangles the segment forms are equal.
		Check if measures of the two angles the segment divides the vertex angle into are the same.
		Check if the segment meets a side of the triangle at a right angle and divides the side into two congruent parts.
		Check if the segment meets a side of the triangle at a right angle and divides the vertex angle into two congruent angles.

mertsj · Answer

The second one.  Bisect means that it divides into two equal parts.