Question

If l, m, n are three lines such that l || m and n $\perp$ l. prove that n $\perp$ m.

Answer 1

The figure can be drawn as follows:

Here, and

We need to prove that .

It is given that, therefore,

(i)

We have, thus,and are the corresponding angles. Therefore,these must be equal. That is,

From equation (i), we get:

Therefore,.

Hence proved.