Prove that two lines that are respectively perpendicular to two intersecting lines intersect each other. [Hint: Use proof by contradiction].
Given: Let lines x and y be two intersecting lines. Let n and p be another two lines which are perpendicular to x and y
To prove: n and p intersect at a point
Proof: Let lines n and p are not intersecting then … (1)
Since n and p are parallel n is perpendicular to x and p is perpendicular to y respectively
So,
But, it is a contradiction as it is given that x and y are two intersecting lines
Thus our assumption is wrong.
n and p intersect at a point
Hence proved