Finding Trigonometric Ratios (5.8.1):

Finding Ratios from Angle of Perspective Demo

Introduction to Trigonometric Ratios Video

Finding Trigonometric Ratios in Right Triangles Video

Cofunction Identities (5.8.2)

Using sine and cosine as complements

Using sine and cosine as complements: another example

Using Trigonometry to Find Missing Sides and Angles (5.9.1)

Finding a Missing Angle Measure in a Right Triangle

Solving a Right Triangle Given One Side and One Angle

Using Trigonometry to Solve Problems (5.9.3)

Solving Problems by Finding a Missing Side Length

Solving Problems by Finding a Missing Angle Measure

Using Trigonometric Identities (5.9.4)

Finding Trigonometric Rations using identities