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VTMO 2026 - Grade 7 - Final - SET 7 - Self-study Question 5

VTMO · VTMO 2026 - Grade 7 - Final - SET 7 - Self-study

Question 5

Triangle $ABC$ is right-angled at A, with $AB\lt AC$, and M is the midpoint of BC. On the ray opposite to MA, choose D with $MD=MA$. Draw perpendiculars from B and C to AD, meeting it at E and F respectively.

a) Prove that $\angle BFD=\angle CEA$.

b) From D draw the perpendicular to BC, meeting BC at K; let DK meet BE at N. Prove that $AN=NC$.

c) If $\angle ABC=60^\circ$, find $\angle ANC$.