2.  A number with a square root is written with the radical.  Use π, not 3.14. › (note: any irrational number is an approximation when written as a decimal)

3.  θ ref is the “Reference Angle” › It is always between 0 ⁰ and 90 ⁰ › It measures the angle between the x-axis and the terminal ray. › Examples:  If θ = 47 ⁰, θ ref = 47 ⁰  If θ = 169 ⁰, θ ref = 11 ⁰  If θ = 252 ⁰, θ ref = 72 ⁰

4.  Angles start their measurements from the positive x-axis.  If the angle is positive, you find the terminal side by rotating counter- clockwise from the starting side. › Note: Angles can be greater than 360 ⁰

5.  All triangles have 6 attributes › 3 sides › 3 angles  Solving a triangle means knowing the values of all 6 attributes › If you are starting with a right triangle, you already know 1 angle! › 2 more attributes are required to SOLVE the triangle  2 sides or  1 side, and 1 angle

6.  Radicals may NOT be in the denominator.  All perfect squares must be removed from inside the radical