Page 25 - ENGINEERING DRAWING

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ii. Constructing perpendicular line

CONSTRUCTION

1. Draw a 100 mm long line AB. Mark a point P on it, at 40 mm from the end A.
2. Set the compass to any convenient radius and with P as the centre, strike arcs to
intersect line AB at C and D.
3. Reset the compass to any radius larger than one-half of CD and with C and D as
centres respectively, strike arcs to intersect at point E.
4. Draw a line from P through E , which is perpendicular to AB.

iii. Constructing perpendicular bisector line

CONSTRUCTION

1. Draw a line AB that is 80 mm long.
2. Set the compass to a radius greater than one – half the length of AB.
3. Set the needle point of the compass at ends A and B respectively. Strike arcs to
intersect at C and D.
4. Draw a line from C through D. The line CD is the perpendicular bisector of AB. Also,

the intersecting point O is the mid-point of line AB.