Cosine

Cosine and sine theorem:
Calculate all unknown values (side lengths or angles) 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 = sin α : sin γ  a=c sinγsinα=c sin14° sin138° =2.9 sin14° sin138° =2.9 0.2419220.669131=8.021=8.0211 cm
b:c = sin β : sin γ  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
Need help calculating sum, simplifying, or multiplying fractions? Try our fraction calculator.
Our percentage calculator will help you quickly and easily solve a variety of common percentage-related problems.
Do you want to convert length units?
Do you want to convert time units like minutes to seconds?
Cosine rule uses trigonometric SAS triangle calculator.
See also our trigonometric triangle calculator.
Try conversion angle units angle degrees, minutes, seconds, radians, grads.

 
We encourage you to watch this tutorial video on this math problem: video1   video2

Related math problems and questions: