CLASS:- 9 EXERCISE:- 5.2 INTRODUCTION TO EUCLID'S GEOMETRY ALL SOLUTION

---

EXERCISE 5.1 EXERCISE 5.2

---

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

solution :

  We can write Euclid’s fifth postulate as ‘Two distinct intersecting lines cannot be parallel to the same line.’

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

solution :

  Yes. If a straight line l falls on two lines m and n such that sum of the interior angles on one side of l is two right angles, then by Euclid’s fifth postulate, lines m and n will not meet on this side of l. Also, we know that the sum of the interior angles on the other side of the line l will be two right angles too. Thus, they will not meet on the other side also.

  ⇒ The lines m and n never meet, i.e, They are parallel.

---

EXERCISE 5.1 EXERCISE 5.2