Question

Given that vectors a+b+c=0 out of three vectors two are equal in magnitude and magnitude of third vector is √2 times that of either of the two having equal magnitude. the angles between vectors are given by

Answer 1

Hello.

A + B + C == 0
Hence A + B == -C
Now as A and B are equal in magnitude and -C is their resultant vector which is root 2 times their magnitude means 
A and B represent adjacent sides of square and -C represent their diagonal.
Therefore angle between A and B is 90 degree and angle between A and C or B and C is 270/2== 135 degrees.

Hope it helps.

Answer 2

Answer:

90°,135°,135°

Step-by-step explanation:

Incase you dont understand the right angled triangle part, Actually what I have done is that I have checked that part by applying the vector formula I.e C=root over( A2+B2+2ABCos theta), so it's coming equal to C only if theta is 90°,I.e cos theta is 0 and thus that part 2AB cos theta whole gets converted to 0 and vanishes.

I hope now you get the clarity.

And yeah when one angle is 90 the other two can easily be found .

Note: This follows polygon law so sum of angles will not be 180° but rather be 360°. Yeah I know I have written it triangle law but that's only when we rearrange the vectors. The second picture shall bring the clarity

Ok.