I need help ASAP
Geometry​

The sum of two numbers is 86, and their difference is 20. find the two numbers

Solve the triangle. a = 21°, c = 105°, c = 5

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.