Try this beautiful problem from the Pre-RMO, 2019 based on Circles,Triangle and largest integer.
Let ABC be a triangle with sides 51, 52, 53. Let D denote the incircle of triangle ABC. Draw tangents to D which are parallel to the sides ABC. let \(r_1\). \(r_2\), \(r_3\) be the inradii of the three corner triangles so formed, find the largest integer that does not exceed \(r_1+r_2+r_3\).
Circles
Triangle
Largest Integers
Answer: is 15.
PRMO, 2019, Question 28
Geometry Vol I to IV by Hall and Stevens
Let PQ be one of tangents parallel to BC and meet sides AB and AC at P and Q let PQ=x and BC=51
triangle ABC similar with triangle APQ then\(\frac{x}{a}=\frac{r_1}{r}=\frac{s-a}{s}\) which is in same way for \(\frac{y}{b}\) and \(\frac{z}{c}\) then \(\frac{r_1+r_2+r_3}{r}\)=\(\frac{x}{a}+\frac{y}{b}+\frac{z}{c}\)=3-2=1
then \(r_1+r_2+r_3\)=r and r by given condition of question =\((\frac{s(s-a)(s-b)(s-c)}{s})^\frac{1}{2}\)=\((\frac{78(78-51)(78-52)(78-53)}{78})^\frac{1}{2}\)=15.
Publishing original scientific research in a peer-reviewed journal is an achievement many scholars work toward for years. Achieving this feat early in one's academic journey requires exceptional intellectual rigor, creativity, and persistence. Aaditya Punatar and Muskan Sadana have reached this remarkable milestone, successfully publishing their collaborative research paper in the prestigious Journal of Emerging Investigators […]
Her project on quantum-accelerated Steiner trees for 15-minute cities earned a place among the finalists at the world's largest pre-college STEM competition. Prishaa Shrimali of Marymount School of New York, was selected as a Grand Finalist at the 2026 Regeneron International Science and Engineering Fair (ISEF) in Phoenix, Arizona. Her project was Optimizing Urban Accessibility: […]
In 2026, the following Cheenta students have been successful for Indian Statistical Institute's M.Stat Entrance. They ranked within the first 50 in the entire country in these entrances. I.S.I. M.Stat Entrance
In 2026, the following Cheenta students have been successful for Indian Statistical Institute's B.Stat Entrance and Chennai Mathematical Institute's B.Sc. Math Entrance. They ranked within the first 200 in the entire country in these entrances. Most of these students attended the problem solving workshops regularly, which happen 5 days every week. CMI B.Sc. Math Entrance […]