Is this relation a function?

I’m not good at math can i have ? ?

Find the center of the circle that can be circumscribed about efg with e(4,4) f(4,2) g(8,2)

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.