Punjab State Board PSEB 9th Class Maths Book Solutions Chapter 5 Introduction to Euclid’s Geometry Ex 5.2 Textbook Exercise Questions and Answers.

## PSEB Solutions for Class 9 Maths Chapter 5 Introduction to Euclid’s Geometry Ex 5.2

Question 1.

How would you rewrite Euclid’s fifth postulate so that it would be easier to understand?

Answer:

‘When a straight line l falls on two other straight lines m and n, it makes four interior angles. If the sum of two interior angles on the same side of line l is 180°, then lines m and n will never intersect each other, i.e., lines m and n are parallel line.

Question 2.

Does Euclid’s fifth postulate imply the existence of parallel lines? Explain.

Answer:

Yes. Euclid’s fifth postulate implies the existence of parallel lines. If a straight line l falls on two straight lines m and n such that the sum of the interior angles on one side of l is two right angles (180°), then by Euclid’s fifth postulate the lines m and n will not meet on this side of l. At the same time, the sum of the Interior angles on the other side of l will also be two right angles (180°). Hence, lines m and n will not meet on that side of l also. Thus, m and n will never meet if the sum of the interior angles on one side is two right angles (180°). This states that lines m and n are parallel.