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Let's do this question in the following figure, Abbi's parallel to D.C. and aid is equal to B.C. Find

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the value of X, so this is an isosceles tropism.

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Pause the video, give it a try and then let's do it together.

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All right.

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We back.

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I hope you have given it a try.

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We are asked to find X in the middle over here.

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We know that these two sides are equal.

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So this is also 10 centimeters right now.

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I can also find that this angle is 120 degrees because these two sides are parallel and this angle and

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this angle have to be supplementary.

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That gives me this angle, 180 minus 60, which is equal to 120 degrees.

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All right.

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Now let's proceed.

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In the case of an isolationist tropism, you will find that this angle and this angle also will be equal.

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So this angle over here is also 60 degrees.

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Now, let me draw the such that D.C. is parallel to S.B.

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So this line is parallel to this line.

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Now, over here, you can see that DEA is splitting the 120 degree angle into two.

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Let me mark this as angle one and let this be angle to.

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All right.

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Now you can see that angle one is equal to angle B, which is equal to 60 degrees, because now the

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C, B, this shape over here, or B, C, D, E, the same is a parallel gram.

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Right.

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Because initially we knew that this side is parallel to the side and reconstructed the such that the

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is parallel to c.B.

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So we have a program over here.

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Therefore opposite angles of a program are equal.

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Therefore angle one over here is equal to 60 degree.

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Angle two will be 120 minus angle one.

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Right.

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So that's one twenty minus sixty which gives you sixty over here.

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So you have this angle of 60 and this angle at 60.

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Therefore this angle also is 60.

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That's 180, minus 60, minus 60.

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So you'll get 60 over here also.

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Therefore, Triangle 80 is an equilateral triangle right now.

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Hence because the sides of any quadrangle are equal and it is given that it is equal to 10 centimeter,

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therefore it also will be equal to 10 centimeters.

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So we know it is equal to 10 centimeter.

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All right.

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Now, Ebbe will be equal to 20 centimeter because B, C, D, E is a program.

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So this is a parallelogram.

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We have seen that over here and we know opposite sides of a program are equal and ebb's equal to twenty

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centimeter.

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All right.

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And over here, you can see X is equal to 80 plus Ebbie.

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That's equal to 10 plus 20.

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And hence the measurement of X is equal to 30 centimeters.

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And that is your answer.