Respuesta :

Answer:

79°

Step-by-step explanation:

Using the cosine rule in ΔABC

cosA = [tex]\frac{b^2+c^2-a^2}{2bc}[/tex]

with a = 14, b = 11, c = 11, then

cosA = [tex]\frac{11^2+11^2-14^2}{2(11)(11)}[/tex] = [tex]\frac{46}{242}[/tex]

A = [tex]cos^{-1}[/tex]([tex]\frac{46}{242}[/tex]) ≈ 79°

Answer:

(A) 79°

Step-by-step explanation:

We can use law of cosine.

c²=a²+b²-2ab*cos(α)

14²=11²+11²-2*11*11*cos(A)

14²=2*11²-2*11²cos(A)

14²-2*11²=-2*11²cos(A)

-46= - 2*(121)*cos(A)

cos(A)= 46/242

arccos(46/242)=79°

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