Cosine

Cosine and sine theorem:
Calculate all missing values from triangle ABC.
c = 2.9 cm; β = 28°; γ = 14° α =? °; a =? cm; b =? cm

Correct answer:

α =  138 °
a =  8.0211 cm
b =  5.6277 cm

Step-by-step explanation:

c=2.9 cm β=28  γ=14   α+β+γ=180° α=180βγ=1802814=138
a:c=sinα:sinγ  a=c sinγsinα=c sin14° sin138° =2.9 sin14° sin138° =2.9 0.2419220.669131=8.021=8.0211 cm
b:c=sinβ:sinγ  b=c sinγsinβ=c sin14° sin28° =2.9 sin14° sin28° =2.9 0.2419220.469472=5.628=5.6277 cm

Try calculation via our triangle calculator.




Did you find an error or inaccuracy? Feel free to write us. Thank you!







Tips for related online calculators
Do you want to convert length units?
Cosine rule uses trigonometric SAS triangle calculator.
See also our trigonometric triangle calculator.

You need to know the following knowledge to solve this word math problem:


 
We encourage you to watch this tutorial video on this math problem: video1

Related math problems and questions: