In the figure below point P1 is at a distance R 138 cm and

In the figure below, point P₁ is at a distance R = 13.8 cm and on the perpendicular bisector of a straight wire of length L = 20.0 cm, carrying a current i = 57.6 mA. (Note that the wire is not long.) What is the magnitude of the magnetic field at P₁ due to i?

B = mu0 i / 4 pi R * L / (L² + R²)^1/2

= (4 pi * 10^-7 * 57.6 * 10^-3 / 4 pi * 13.8 * 10^-2) * (0.20 / (0.20² + 0.138²)^1/2)