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Two lines a and b are intersected by a transversal c prove that a//b, if

NEED IN 15 min am giving ABOUT 50 POINTS
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Two lines a and b are intersected by a transversal c prove that a//b, if NEED IN 15 min-example-1

1 Answer

4 votes

Answer:

Because Alternate Interior angles are equal.

Explanation:

STEP - I:


$ m \angle {5} = 3 . m \angle {\{3}\} $

Reason:

This is the given data.

STEP - II:

It has multiplied and the reason is mentioned as well.

STEP - III:


$ m \angle{3} + m \angle{5} $ = 45° + 135° = 180°

Reason:

It has substituted the value of
$ m\angle{5} $ from the previous step. The sum of
$ m\angle{3} $ and
$ m \angle{5} $ is 180°.

STEP - IV:


$ a \parallel b $

Reason:

We calculated
$ m\angle{5} to be 135°.

Note that
$ \angle {5} $ and
$ \angle{6} $ are on the same line. That means their sum should be 180°.

i.e.,
$ m\angle{5} + m\angle{6} $ = 180°.


$ \implies $ 135° +
$ m\angle{6} $ = 180°.


$ \implies m\angle{6} = $ 45°.

One of the ways to prove
$ a \parallel b $ is to check if alternate interior angles are equal.

Here,
$ m\angle{3} $ and
$ m \angle {6} $ are alternate interior angles and they are equal.


$ \implies a \parallel b $.

User Anand Kore
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