Obtuse Angles

Obtuse Angle Formulas

sinθ = sin(180° − θ)

cosθ = −cos(180° − θ)

tanθ = −tan(180° − θ)

Video Summary

Explore!

Use the applet below to observe how the length of the hypothenuse, opposite and adjacent sides change when the reference angle is obtuse.

Note the relationship between the trigonometric ratio obtuse angle with the acute angle (Basic Angle) equivalent.

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