4. Represent on the number line.
Draw a line segment AB of 9.3 units.
Then, extend it to C so that BC = 1 unit.
Find the mid-point O of AC and draw a semi-circle on AC while taking O as its centre and AO as the radius.
Now, Draw a perpendicular to line AC passing through point B and intersecting the semi-circle at D.
Now, Take B as the centre and BD as the radius, and draw an arc intersecting the number line at E.
The length BE is $\sqrt{9.3}$ units.