1. **Problem Statement:**
(i) Show that any two angle bisectors of a triangle meet in a point.
(ii) Show that the three angle bisectors of a triangle meet in a point.
2. **Key Concept:**
An angle bisector of a triangle is a line segment that divides an angle into two equal parts and extends from a vertex to the opposite side.
3. **Step (i): Two angle bisectors meet in a point**
- Consider triangle ABC with angle bisectors from vertices A and B.
- Let the angle bisector from A meet side BC at point D, and the angle bisector from B meet side AC at point E.
- By the Angle Bisector Theorem, these bisectors divide the opposite sides proportionally.
- The two bisectors intersect at a point I inside the triangle because each bisector is a line segment inside the triangle.
4. **Step (ii): Three angle bisectors meet in a point (Incenter)**
- Let the third angle bisector from vertex C meet side AB at point F.
- We need to show that the three bisectors intersect at a single point I.
- Since I lies on the bisector of angle A and angle B, it is equidistant from sides AB and AC, and from sides AB and BC respectively.
- By definition, the point equidistant from all sides of a triangle is the incenter.
- Therefore, the third bisector from C also passes through I, proving concurrency.
5. **Summary:**
- Any two angle bisectors intersect at a point inside the triangle.
- The third angle bisector also passes through this point, so all three bisectors are concurrent.
- This point is called the incenter, the center of the inscribed circle of the triangle.
This completes the proof that the three angle bisectors of a triangle meet in a single point.
Angle Bisectors E28Ee1
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