Difference between revisions of "1998 IMO Problems/Problem 5"
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+ | ==Problem== | ||
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Let I be the incenter of triangle ABC. Let the incircle of ABC touch the sides | 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 | 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 | to M K meets the lines LM and LK at R and S, respectively. Prove that angle | ||
RIS is acute. | RIS is acute. | ||
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+ | ==Solution== | ||
+ | {{solution}} | ||
+ | |||
+ | ==See Also== | ||
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+ | {{IMO box|year=1998|num-b=4|num-a=6}} |
Revision as of 22:50, 18 November 2023
Problem
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.
Solution
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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 |