Finding the angle between vectors a and m, knowing the magnitude of m and n

[piesand]

Summary: Finding angle between vectors a and m, knowing magnitude of m and n, also the angle between m and n with 60 degrees.

Using geometry, it looks like the angle is 30 degrees but the answer is suppose to be 54.7 degrees. I'm not sure how to solve this.

 

[Abhishek11235]

Hint:
$$\cos \theta= \frac {\vec a . \vec m}{||\vec a|| ||\vec m||}$$

 

[ehild]

Summary: Finding angle between vectors a and m, knowing magnitude of m and n, also the angle between m and n with 60 degrees.

View attachment 252831

Using geometry, it looks like the angle is 30 degrees but the answer is suppose to be 54.7 degrees. I'm not sure how to solve this.

Sometimes the given answer is not true. Show, please, how did you get your result. It might be correct