## Online Course Discussion Forum

### Math Challenge IV Fall Week 1 HW

I've spent way too long on Example 6, and have only completed the first part.

So I have: DE=DF implies AEDF is cyclic, and I am trying to prove angle EDF is acute for part b, but I have not found a helpful angle chase. Is this approach correct, and if so, what should I be looking for in my angle chase?

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