Determine how (if possible) the triangles can be proved similar

The median am of triangle ∆abc is half the length of the side towards which it is drawn, bc . prove that triangle ∆abc is a right triangle, and find angle mac and abm

Which equation is represented by the graph below?

The pyraminx is a rubik's cube-type toy in the shape of a tetrahedron. the pyraminx shown below has edges 15\,\text{cm}15cm long and vertical height h=12.2\,\text{cm}h=12.2cm. the triangle drawn with dashed lines is a right triangle. what is the distance rr? round your answer to the nearest tenth.