[b][color=#ff00ff]1) The pink angle measures 30 degrees = pi/6 radians. [br][/color][/b][br]2) This applet illustrates (what many texts refer to as) "reference triangles" for angles (drawn in standard position) are multiples of [b][color=#ff00ff]30 degrees = pi/6 radians.[/color][/b] [br][br]3) Each triangle shown is a 30-60-90 triangle.[br][br]4) The [color=#9900ff][b]hypotenuse[/b][/color] of a 30-60-90 triangle is [b][color=#9900ff]double the length[/color][/b] of the triangle's [color=#9900ff][b]shorter leg[/b][/color]. [br][br]5) Values of the six main trigonometric functions evaluated at the angles described in (2) can be determined from this diagram. (Ex: sin(30 deg) = y/r = 1/2).