Sometimes you may
need to find the exact centre of a line you have drawn on a plan,
here's a simple and accurate method you can employ using a
compass.
Set the end of the compass at one end (B) of the
line and draw an arc at any point beyond the halfway point.
Move the compass to the opposite end of the line
(A) and, retaining the exact compass setting, draw an arc from
that point.
Now draw a straight line from the points where
the two arcs cross at the top (C) to the point where the arcs
cross at the bottom (D). The centre of the line is at the exact
point where this line crosses the line you are measuring.
Another handy tip
from Coates Mitre 10 Home & Trade Lithgow
