help please, i need to show work. (no links!)

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

Aquadrilateral has exactly one pair of parallel sides. which name best describes the figure?

Suppose you are choosing a 6-digit personal access code. this code is made up of 4 digits chosen from 1 to 9, followed by 2 letters chosen from a to z. any of these digits or letters can be repeated. find the total number of personal access codes that can be formed. 492,804 341,172 39,917,124 4,435,236