1998 IMO Problems/Problem 5


Let I be the incenter of triangle ABC. Let the incircle of ABC touch the sides BC, CA, and AB at K, L, and M , respectively. The line through B parallel to M K meets the lines LM and LK at R and S, respectively. Prove that angle RIS is acute.


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See Also

1998 IMO (Problems) • Resources
Preceded by
Problem 4
1 2 3 4 5 6 Followed by
Problem 6
All IMO Problems and Solutions