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MathNet 2020 — Math Olympiad Vault — Part 05 Question 48

Math Olympiad Vault · MathNet 2020 — Math Olympiad Vault — Part 05

Question 48

Let $ABC$ be a right triangle with $\angle BAC=90^\circ$, and let $I$ be the intersection of its angle bisectors. A line through $I$ meets sides $AB$ and $AC$ at $P$ and $Q$, respectively. The distance from $I$ to $BC$ is $1~\mathrm{cm}$.

a) Find $PM\cdot NQ$.

b) Find the minimum possible area of triangle $APQ$.

Hint: If $x,y$ are nonnegative real numbers, then $x+y\ge2\sqrt{xy}$.

Question illustration