We were introduced to the sine and cosine function as ratios of the sides of a triangle drawn inside a circle and spent time discussing the role of those functions in finding points on the circle. In this section, we return to the triangle and explore the applications of the trigonometric functions to right triangles where circles may not be involved.
Right Triangle Trigonometry (Trigonometry & Precalculus)
Subject
Math — Mathematical Functions
Grade Level
Grades 9-12
Resource Type
Lesson Plan
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State-specific
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Basic trigonometry | Basic trigonometry | Trigonometry | Khan Academy
Angle to aim to get alien | Basic trigonometry | Trigonometry | Khan Academy
Example: Trig to solve the sides and angles of a right triangle | Trigonometry | Khan Academy
Standards
Use special triangles to determine geometrically the values of sine, cosine, tangent for π/3, π/4 and π/6, and use the unit circle to express the values of sine, cosine, and tangent for π–?, π+?, and 2π–? in terms of their values for ?, where ? is any real number.
Understand that by similarity, side ratios in right triangles are properties of the angles in the triangle, leading to definitions of trigonometric ratios for acute angles.
