Question

A=3.5, b =6.9, c=4.7
whats the measure of angle a?​

Answer 1

27.66°

Explanation:

From the law of cosines, ...

a² = b² +c² -2bc·cos(A)

cos(A) = (b² +c² -a²)/(2bc)

A = arccos((b² +c² -a²)/(2bc))

A = arccos((6.9² +4.7² -3.5²)/(2·6.9·4.7)) = arccos(57.45/64.86)

A ≈ 27.66°

The measure of angle A is about 27.66°.