. In a soccer league, each of the n participating teams plays every other team twice during the season. If in the next season the league increases the number of teams by two, then there would be 27.5% more matches played. Find

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.