represent root 8.4 on number line

steps are :-

1.  draw a line segment AB=8.4 units.
2. from B mark a point C on the number line where BC= 1 unit.
3. then find the centre of line segment  AC by drawing a preprndicular bisector and name it as D.
4. by taking D as centre and radius DC draw a semicircle.
5. draw a prependicular at point B which cuts semi circle at E.
6. then by taking B as centre and BE radius, draw an arc which cuts number line and mark the point as F.
7. here point F represents underroot 8.4..

Hope it helps..... :):):)