Mastery Challenge: Definition of an Angle, Solving for the Angle on a Right Triangle

The first task was to define an angle. The definition of an angle is the point of intersection between two rays. The measurement of an angle is the amount of space between two rays in a specific way. To solve the angle of a right triangle, use the proper trigonometric ratio with the "-1" on it.  Divide the correct lengths by each other then put the quotient in the trigonemetric ratio to get the answer. The screenshots below will help you understand the given tasks on Khan Academy.