Please explain question 4
Dear Student,
(1) Draw a line segment
of 12.8 cm.
(2) Draw a circle, while taking point X as centre and radius more than half of XY.
(3) With same radius and taking centre as Y, again draw arcs to cut the circle at A and B. Join AB which intersectsat M.
(4) Taking X and Y as centres, draw two circles with radius more than half of
.
(5) With same radius and taking M as centre, draw arcs to intersect these circles at P, Q and R, S.
(6) Join PQ and RS. These are intersectingat T and U.
(7) Now, 
. These are 4 equal parts of.
By measuring these line segments with the help of ruler, we will find that each is of 3.2 cm.
Regards,