Given OX= ½ XY => 2 OX = XY ……….(i)
PX= ½ XZ => 2 PX = XZ …….(ii)
and OX = PX …(iii)
According to Euclid’s axiom, things which are double of the same things are equal to one another.
On multiplying Eq. (iii) by 2, we get
2 OX = 2 PX
XY = XZ. [from Eqs. (i) and (ii)]