Find Side BC and round to the nearest tenth of a decimal

Which best explains why this triangle is or is not a right triangle?

International calls require the use of a country code. many country codes a 3-digit numbers. country codes do not begin with a 0 or 1. there are no restrictions on the second and third digits. how many different 3-digit country codes are possible?

Which of the following is most likely the next step in the series? a3z, b6y, c9x, d12w, е15v, f18u