# Nine-point circle is tangent to ex-circle

Prove that nine-point circle is tangent to ex-circles of a triangle.

• Without using the technique of inversion.

I've known the proof that nine-point circle is tangent to incircle without using this technique before, but not the excircle. Please help me!

Note by Samuraiwarm Tsunayoshi
3 years, 3 months ago

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1. Can you state the proof that the nine-point circle is tangent to the incircle?
2. Why does this proof not work when applied to the excircle?

Staff - 3 years, 3 months ago