Warm Up. How’d the test go? Better? Worse? Did you do anything different to study for this test? How many times have you attended tutoring? Did you do every homework assignment for the unit?. Circular Trig. Basic Terms. An angle is formed by rotating a ray around its endpoint.
A complete rotation of a ray results in an angle measuring 360.
We don’t have to stop there!
(Add or subtract 360 as may times as needed to obtain an angle with measure greater than 0 but less than 360.)
a) 1115 b) 187
a) 1115° - 360° - 360° - 360° = 35°
b) 187 + 360 = 173
Think about what the word radian sounds like… it sounds like “radius,” right? It turns out that a radian has a close relationship to the radius of a circle.
Example 3: Convert each degree measure to radians.
(a) 30° (b) 120° (c) 60° (d) 270° (e) 104 °
Example 3: Convert each radianmeasure to degrees.
Write these down in your notes! If you memorize them, it will make converting from radians to degrees (and vice versa) much easier!