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 = 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

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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.

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