Answer: segment KH
Explanation:
The altitude of a triangle is defined as a segment connecting one of the vertex of the triangle with the opposite side of the triangle (or with an external prolongation of it), forming a right angle with it.
Note that the altitude of a triangle can also be outside the area of the triangle.
If we look at the picture, we see that:
- IH is a side, so it is not an altitude of the triangle
- KH is an altitude of the triangle, since it connects the vertex H with the external prolongation of IG, and it makes a right angle with it
- GJ: we don't know if it is an altitude, since we don't know if it forms a right angle or not
- GH: it is a side of the triangle, so it is not an altitude
So, the correct answer is segment KH.