1 / 5

Sine Rule for Angles

P. Q. R. 18 20. =. sin42 ° sinQ°. p q r. = =. sinP sinQ sinR. Sine Rule for Angles. Ex1. 42 °. 20cm. 18 X sinQ ° = 20 X sin42°. sinQ ° = 20 X sin42°  18. 18cm. sinQ ° = 0.743…. (min 3 dps). Find angles Q and R. Q ° = sin -1 0.743. = 48 °. . .

airlia
Download Presentation

Sine Rule for Angles

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. P Q R 18 20 = sin42° sinQ° p q r = = sinP sinQ sinR Sine Rule for Angles Ex1 42° 20cm 18 X sinQ° = 20 X sin42° sinQ° = 20 X sin42°  18 18cm sinQ° = 0.743…. (min 3 dps) Find angles Q and R. Q° = sin-10.743 = 48°   R° = 180° – 42° - 48°  ? ? = 90°

  2. F G H 30 17 = sin72° sinH° f g h = = sinF sinG sinH Ex2 72° 17cm 30 X sinH° = 17 X sin72° sinH° = 17 X sin72°  30 30cm sinH° = 0.539.…. (min 3 dps) Find angles G and H. H° = sin-10.539 = 32.6°   R° = 180° – 72° - 32.6°  ? ? = 75.4°

  3. Ex3 3.2 1.7 X = sinc° sin32° 3.2m 1.7m x y z c° = = 32° Y Z sinX sinY sinZ In a lop-sided roofthe longer side is 3.2m and slopes at an angle of 32° to the horizontal. The shorter side is 1.7m and makes an angle of c° with the horizontal. Find c°. 3.2m 1.7m c° 32° 1.7 x sinc° = 3.2 x sin32° sinc° = 3.2 x sin32°  1.7  sinc° = 0.997  c° = sin-10.997  ? = 86°

  4. Obtuse Angles A B A+B sinA° sinB° 20 160 180 0.342 0.342 35 145 180 0.574 0.574 70 110 180 0.940 0.940 43 137 180 0.682 0.682 CONCLUSION If A + B = 180 then sinA° = sinB° Ex4 sinx° = 0.643 so x = sin-10.643 = 40° or 140°

  5. B 4cm A 30° C 7cm a b c = = sinA sinB sinC Ex5 In ABC a = 4, b = 7 & angle A = 30°. Find two possible sizes for angle B. 

More Related