Solution:
Mark a line segment $\mathrm{OB}=9.3$ on number line. Further, take $\mathrm{BC}$ of 1 unit. Find the mid-point $\mathrm{D}$ of $\mathrm{OC}$ and draw a semi-circle on $\mathrm{OC}$ while taking $\mathrm{D}$ as its centre. Draw a perpendicular to line OC passing through point B. Let it intersect the semi-circle at E. Taking B as centre and BE as radius, draw an arc intersecting number line at $F$. BF is $\sqrt{9.3}$.
Mark a line segment $\mathrm{OB}=9.3$ on number line. Further, take $\mathrm{BC}$ of 1 unit. Find the mid-point $\mathrm{D}$ of $\mathrm{OC}$ and draw a semi-circle on $\mathrm{OC}$ while taking $\mathrm{D}$ as its centre. Draw a perpendicular to line OC passing through point B. Let it intersect the semi-circle at E. Taking B as centre and BE as radius, draw an arc intersecting number line at $F$. BF is $\sqrt{9.3}$.