I am not quite sure what the question asks for,
But this is what i assume it wants:
Cos A= 0.6489
In this given one, we basically find the size of the angle A
we do cosine inverse on both sides to get the size of the angle A
[tex] cos^{-1} [/tex] : It looks like this in the calculator
[tex] cos^{-1} [/tex] × cos A=[tex] cos^{-1} [/tex](0.6489)
([tex] cos^{-1} [/tex] and cos cancels out)
A=[tex] cos^{-1} [/tex](0.6489)
A=49.54°
check:
cos 49.54=0.6489 (its right!)
