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VTMO 2026 - Grade 9 - Final - SET 10 - Self-study Question 5

VTMO · VTMO 2026 - Grade 9 - Final - SET 10 - Self-study

Question 5

Let $(O)$ be the circle with diameter $AB$, and let $C$ be any point on segment $AB$. Construct circles $(O_1),(O_2)$ with diameters $AC,CB$. Let $M$ lie on $(O)$, distinct from $A,B$, and let $ME,MF$ be tangents to $(O_1),(O_2)$, touching at $E,F$.

a) Prove $\left(\dfrac{ME}{MA}\right)^2+\left(\dfrac{MF}{MB}\right)^2=1$.

b) Find $C$ such that $ME=\dfrac12MA$.