(i) 1. Construct a line AB.
2. Construct lines l and m parallel to AB at a distance of 2.5 cm.
now,
lines l and m are the locus of point P at a distance of 2.5 cm.
(ii) According to ques,
Δ ABC is an isosceles triangle where AB = AC.
Taking A as centre construct a perpendicular AD to BC.
Here AD is the locus of point A which are the vertices of Δ ABC
In Δ ABD and Δ ACD
The sides AD = AD is common
according to ques,
Hypotenuse AB = AC
According to RHS Axiom
Δ ABD = Δ ACD
BD = DC (c.p.c.t)
hence, locus of vertices of isosceles triangles having common base is the perpendicular bisector of BC.