Confused on Vector Math: Find Resultant Vector

[AryRezvani]

Homework Statement

Homework Equations

x^2 + y^2 = r^2

The Attempt at a Solution

I understand everything, but the last segment.

What vector B when added to vector A, gives a resultant vector with no x component and a negative y component 3.34 units in length?

So 3.34 = Sqr Root [(0^2) + (y^2)]

You get 3.34 again, and because it states the y component should be negative, I plugged in -3.34, but alas, it's wrong. -.-

Ignore the 2.12 that I plugged in on the screenshot, I was just trying different ways of working this out.

 

[Doc Al]

They want the j component of A + B to equal -3.34. Do your values for the j components add to -3.34? (Set up a simple equation and solve for B_y.)

 

[AryRezvani]

They want the j component of A + B to equal -3.34. Do your values for the j components add to -3.34? (Set up a simple equation and solve for B_y.)

Thanks.