If you are asked to draw locus of points that are all 4cm from a point, that means you have to draw a circle with a radius of 4cm.
If you are asked to draw locus of points that are 3cm from a given line, that means you have to draw 2 parallel lines with the distance of 3cm to the given line.
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If you are asked to draw locus of points that are 4cm of a given line segment, that means you have to draw 2 parallel lines and semicircle at the right side and left side of the line. The shape would be like this:
ncetm.org.uk
That's the end of this session. Thank you!