Is it impossible to construct an equilateral triangle inside a semicircle?

Question

I have made it in a circle(which is very easy)....but I have been unable to make one inside a semicircle....is it not possible to make equilateral triangle inside a semicircle ?... If yes how can we prove it (please give the proof or the steps I need to take to prove it) ...? If no can anyone give me some examples of such equilateral triangle/semicircle.

Note: By constructing an equilateral triangle inside a semicircle I mean that all the vertices should lie on the arc(of the semicircle).

Edit: sorry for the confusion caused (I have deleted that comment )for this question the vertex cannot lie on the diameter..

Answer 1

Yes, it's impossible. Note that must exist an angle obtuse in this triangle, because the diameter generates angles of 90°.