I couldn’t find an introductory Pythagoras activity where students have to label the hypotenuse that included non-right angled triangles, so I made one. Either for students to complete themselves (perhaps a bit quick for that!) or an activity on the board. The main point I want to make here is that only right angled triangles have a hypotenuse, and we need to see the right angle labelled to know a triangle is right angled.