In triangle ABC, the circumcenter and orthocenter are collinear with vertex A. Which of the following statements must be true?

1) Triangle ABC must be an isosceles triangle

2) Triangle ABC must be an equilateral triangle

3) Triangle ABC must be a right triangle

4) Triangle ABC must be an isosceles right triangle

There could me more than one answer, and if none of these are correct, just say none.

Thanks!

Guest Oct 28, 2021