(Solved): The figure shows two displacement vectors A and B. Vector A points at an angle of 21.0 above the ...

The figure shows two displacement vectors $$\vec{A}$$ and $$\vec{B}$$. Vector $$\vec{A}$$ points at an angle of $$21.0^{?}$$ above the $$x$$ axis and has an unknown magnitude. Vector $$\vec{B}$$ has an $$x$$ component $$B_x=39.0\mathrm{m}$$ and has an unknown $$y$$ component $$By$$. These two vectors are equal. Find (a) the magnitude of $$\vec{A}$$ and (b) the value of $$B_y$$. (a)