Gr. 12 Vectors Question

[Katykat0807]

The angle between vectors a and b is 140°. The angle between vectors c and b is 70°. If a, b and c are in equilibrium,
A) determine the angle between vectors a and c
B) determine the magnitude of vectors b and c if |a| = 10

Thanks in advance!
I accidentally hit solved but i haven’t

 

[Deleted member 4993]

View attachment 12321
The angle between vectors a and b is 140°. The angle between vectors c and b is 70°. If a, b and c are in equilibrium,
A) determine the angle between vectors a and c
B) determine the magnitude of vectors b and c if |a| = 10

Thanks in advance!
I accidentally hit solved but i haven’t

If vectors a, b & c are in equilibrium, those must construct a triangle if you place those head to tail.

What does that tell you about the sum of the angles between the vectors?

What does that tell you about the angle between a & c?

To solve (b), use law of sines.