9th Maths 5.2
NCERT Class 9th solution of Exercise 5.1
Exercise 5.2
Q1. How would you rewrite Euclid's fifth postulate so that it would be easier to understand?
Answer :
If a straight line intersects two other straight lines and the sum of the two interior angles formed on the same side is less than two right angles (180°) then the two-line are intersecting lines.
Q2. Does Euclid's fifth postulate imply the existence of parallel lines? Explain.
Answer :
If a straight line `l` falls on two straight 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 the line will not meet on this side of `l`. Next, you know that the sum of the interior angles on the other side of line `l` will also be two right angles. Therefore, they will not meet on the other side also. So, the lines `m` and `n` never meet and are, therefore, parallel.
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