locus of a point
A straight-line AB is 8 cm long. Draw and describe the locus of a point which is: always 4 cm from the line AB
Draw a line segment AB of length 8 cm.
Draw two parallel lines l and m to AB at a distance of 4 cm.
Draw the perpendicular bisector of AB which intersects the parallel lines l and m, at X and Y respectively then, X and Y are the required points.
Join AX, AY, BX and BY.
The figure AXBY is a square as its diagonals are equal and intersect at 90o.