The magnetic field at the center of current carrying circular loop...

Magnetic field at the centre of the loop i.e.& ${B}_{1} = \dfrac{{μ}_{0}i}{2R}$

Magnetic field on the axis of the loop is,

${B}_{2} = \dfrac{{μ}_{0}iR^{2}}{2\left(R^{2} + x^{2}\right)\dfrac{3}{2}} = \dfrac{{μ}_{0}i \times R^{2}}{2\left(R^{2} + 3R^{2}\right)\dfrac{3}{2}}= \dfrac{{μ}_{0}i \times R^{2}}{2 \times 8R^{3}}= \dfrac{{μ}_{0}i}{2 \times 8R}$

Therefore, the ratio~$\dfrac{B1}{B2} = \dfrac{8}{1}$