If you take out a loan for $4,000 and you will owe $4,920 after 2 years, what is the rate of simple interest? express your answer as a percentage rounded to the nearest tenth of a percent if necessary, but do not include the percent sign.

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.