1 / 10

Sine Rule – Finding an Obtuse Angle

Sine Rule – Finding an Obtuse Angle. Evaluate (a) sin 30° (b) sin 150° (c) sin 60° (d) sin 120° (e) cos 40° (f) cos 140° (c) cos 10° (d) cos 170°. Evaluate (a) sin 30°= 0.5 (b) sin 150°= 0.5 (c) sin 60°= 0.866.. (d) sin 120°= 0.866..

graiden-brady
Télécharger la présentation

Sine Rule – Finding an Obtuse Angle

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Sine Rule – Finding an Obtuse Angle

  2. Evaluate • (a) sin 30° (b) sin 150° • (c) sin 60° (d) sin 120° • (e) cos 40° (f) cos 140° • (c) cos 10° (d) cos 170°

  3. Evaluate • (a) sin 30°= 0.5 (b) sin 150°= 0.5 • (c) sin 60°= 0.866.. (d) sin 120°=0.866.. • (e) cos 40°=0.766.. (f) cos 140°=-0.766.. • (c) cos 10°=0.984.. (d) cos 170°=-0.984..

  4. Note that the sine of an acute angle and its (obtuse) supplement are the same.

  5. Note that the sine of an acute angle and its (obtuse) supplement are the same. • That means that any sine rule problem involving the missing angle could have two answers (an acute and obtuse).

  6. Note that the sine of an acute angle and its (obtuse) supplement are the same. • That means that any sine rule problem involving the missing angle could have two answers (an acute and obtuse). • In this course we assume the acute-angled answer, unless the obtuse angled answer is specifically requested.

  7. Example: • Find the value of θ to the nearest degree if it is obtuse.

  8. Example: • Find the value of θ to the nearest degree if it is obtuse. 10 m 5 m 22° θ

  9. Example: • Find the value of θ to the nearest degree if it is obtuse. 10 m 5 m 22° θ

  10. Example: • Find the value of θ to the nearest degree if it is obtuse. • But θ is obtuse. • Therefore θ = 180 – 48.52222.. • ≈ 131° 10 m 5 m 22° θ

More Related