Simplify the complex fraction. 2/3m-1/2m 3m/3+4/5m​

15/16 as a decimal rounded to the nearest hundredth

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.

Based on the diagrams, what is the value of x?