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Let's do this question, find the value of B. over here, this Angliss three B and we need to find the

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value of B, all right.

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

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All right.

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We are back in this picture.

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You can see that angle C or B is equal to angle B or Q, why is that so?

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And you remember why that is so.

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Yes, because these two angles are vertically opposite angles.

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Right.

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And vertically opposite angles are equal to each other.

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Therefore, Angle B or Q is equal to a hundred degree.

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Now these three angles, if we add them right, we should get 180 degrees because they form a straight

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angle.

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Right.

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Because a B is a straight line and we remember a straight angle is equal to 180 degrees.

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Therefore angle B or A plus angle B or Q plus angle Q or B is equal to 180 degrees.

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All right.

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Now B or is to any degree B or Q is hundred degree and Q or B is equal to three B, therefore three

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B is equal to 180 minus 120, which is equal to 60 degrees.

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Or you get B's equal to 20 degrees.