T1-3: Trigonometry

T1-3: Trigonometry

1. Vocabulary

   • angle of elevation
     • the angle between the horizontal through eye level and a line of sight to a point above eye level
   • angle of inclination
     • the acute angle between the horizontal and a line or line segment
   • angle of depression
     • the angle between the horizontal through eye level and a line of sight to a point below eye level
   • indirect measurement
     • a direct measurement made using a ratio, formula or other mathematical reasoning

2. Types of trig ratios and what they do

   • tangent
     • finds an angle when you have the opposite and the adjacent side length
   • sine
     • used to find an angle when you have the opposite side length and the hypotenuse length
   • cosine
     • used to find an angle when you have the adjacent side length and the hypotenuse length

3. Concept summary

   • You can solve problems that involve more than one right triangle by applying the necessary trig ratios one at a time
   • You can use a tangent, cosine or sine ratio to create an equation. you can then solve the equation to find out the unknown side length
   • If the tangent, sine or cosine ratio of an angle is known the related inverse operation can be used to determine the measure of the angle

4. Trig ratio equations

   • Tangent
     • opposite side length/adjacent side length
   • Sine
     • opposite side length/length of hypotenuse
   • Cosine
     • adjacent side length/hypotenuse length