Question

prove that every line segment has only one and one midpoint​

Answer 1

Answer:

Step-by-step explanation:

Let us consider, a line segment AB.

Assume that it has two midpoints say C and D

 Recall that the midpoint of a line segment divides it into two equal parts

That is AC = BC and AD = DB

Since C is midpoint of AB, we have A, C and B are collinear

∴ AC + BC = AB → (1)

Similarly, we get AD + DB = AB → (2)

From (1) and (2), we get

AC + BC = AD + DB

2 AC = 2AD

∴ AC = AD

This is a contradiction unless C and D coincide.

Therefore our assumption that a line segment AB has two midpoints is incorrect.

Thus every line segment has one and only one midpoint.

Answer 2

Answer:

Suppose C and C' are two mid points of segment AB

Then AC = AB

and AC' = AB

AC = AC' [Things which are equal to the same thing are equal to one another.]