Adding Vector Problem: Is There More?

[3301]

Ive done the basic trig functions and the result is different. It came out as 45 45 90 triangle and i found the h for it and done sin45 = h/c to get vector C. Am i missing something with vectors?

 

[Let'sthink]

Assuming magnitudes of vector a and vector be be to be equal to |a|, the resultant will have magnitude = 2*|a|*sin (45/2)

 

[3301]

Thanks for respond but i was just about to say that i solved it. It was my fault in squaring formula.