# How can I find the Magnetic Field at the point without using law of cosines

There are two parallel wires, both carry currents of $I=16.5A$ in the same direction.

The wire on the left is $B_1$ and the one on the right is $B_2$

That said I know from $B=\frac{\mu_0 I}{2\pi R}$:

$$B_1=2.7500\times10^{-5}\,\text{T}$$ $$B_2=2.5385\times10^{-5}\,\text{T}$$ Since this triangle has three diferent sides, this allows to use law of cosines. However, is there other way to solve it?

You are right, but this rule applies only for infinite wires, otherwise use Bio-Savart-Laplace equation $$\vec{B}=\frac{\mu_0}{4\pi} \int _{C}{\frac {Id\mathbf {l} \times \mathbf {{{r}}'} }{|\mathbf {r''} |^{2}}}$$ Where $r'$ is a location of infinitesimal element of a current-carrying wire and $r''$ - observation point (where you want to calculate)