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Let's do this problem in the given figure, find out which pair of lines are parallel.

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All right, what's the video?

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Give it a try and then let's do it together.

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All right.

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We're back.

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I hope you have given it a try.

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Let's do it together over here.

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Let me mark these two angles, this angle, one angle, too, OK?

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Now let's check whether nine Abe is parallel to nine city.

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If these two lines were parallel and DH is acting as a transversal, we know that consecutive interior

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angles or interior angles on the same side of the transversal should be supplementary.

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Right.

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But one plus two should give you a 180 degree if Abe was parallel to it.

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Now, if you add angle one and angle two, you will get your answer as one seventy nine.

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Right.

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One twenty two plus fifty seven gives you one seventy nine.

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That's not equal to 180 degrees.

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Therefore Abe is not parallel to city.

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All right, let's move on now over here.

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Angle two is fifty seven degree and this angle over here is also fifty degrees because they are vertically

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opposite angles.

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Let me mark this angles three and this one is four.

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OK, so we have two angles over here.

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Now, if I add three and four, I should get 180 degrees in the case that ECF and they are parallel.

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Right, because well F and get Kitty is acting as the transversal.

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So if you are angled three plus angle four, that's one twenty three plus fifty seven and that gives

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you 180 degree.

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Therefore we can conclude that EAF is parallel to get let's that over here.

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We have identified two lines that are parallel now over here.

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This angle is fifty five degrees.

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Therefore this angle over here also will be fifty five degrees because they are vertically opposite

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angles.

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Right.

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All right.

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So let me make this angle as angle five.

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OK, now angle to angle five.

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They are corresponding angles, right.

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The corresponding angles for these two lines, Edge and KP and Chris is acting as the transversal right.

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The Edge and KP.

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These are the two lines and Chris is intersecting both the lines, the series acting as the Transversal.

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So we can see that angle to angle five are corresponding angles.

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Now, if these two lines were parallel, we know that corresponding angles have to be equal.

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But over here and the two is fifty seven degrees and angle five is fifty five degree.

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Angle two is not equal to angle five.

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Therefore gets is not parallel to KP.

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Right.

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So is there any other line said set of lines that are parallel.

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No, we have seen that these two lines are parallel, we have seen that edge and KP are not parallel.

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So definitely E, F and KP also will not be parallel.

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Right, because these two are parallel.

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Alright now over here we have also seen that it is not parallel to city.

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So in this figure which is given the only set of lanes which are parallel is E, f and.

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G.H., that is your answer.

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Remember, if you have two lines that are parallel to each other and if you find that a third line is

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not parallel to one of these lines, definitely that third line will not be parallel to the other line

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as well.

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Right.

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If these two are not parallel, if you keep extending them, they will intersect at some point.

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Now, because these two are parallel, they will never intersect.

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But if these two are not parallel and these two are parallel, as is the case in this question, therefore,

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remember, these two lines also will not be parallel.