Trigonometric Ratios (Sine, Cosine, Tangent)

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Last updated: 8/16/2025

Key Concepts:

  • The three primary trigonometric ratios for right triangles:
    • (\sin(\theta) = \frac{opposite}{hypotenuse})
    • (\cos(\theta) = \frac{adjacent}{hypotenuse})
    • (\tan(\theta) = \frac{opposite}{adjacent})
  • Trigonometric identities:
    • (\sin A = \cos(90^\circ - A), \cos A = \sin(90^\circ - A))
    • (\tan A = \frac{\sin A}{\cos A})
    • (\sin^{2}x + \cos^{2}x = 1)

Skills Covered:

  • Calculating sin, cos, and tan for an angle given side lengths or other trigonometric ratios.
  • Finding a missing side length of a right triangle using trigonometric ratios.

Example Problems:

  • In right triangle (ABC), (C) is (90°), (AB = 29), (BC = 21). Find (sin A).
  • If (cos x = \frac{24}{25}), calculate (sin x).

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