angle 1=angle 4 and angle 3 =angle 2. by which euclid's axiom , it can be shown that if angle 2= angle 4 then angle1= angle 3.

It can be shown by Euclid's first axiom which states that:

"Things which are equal to the same things are equal to one another."

Here, angle 1 = angle 4 ......(1)

angle 3 = angle 2 ......(2)

If, angle 2 = angle 4

then, angle 3 = angle 1 [Substituting values of angle 2 and angle 1 from (1) and (2)]

or, angle 1 = angle 3

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