Let's do this question in the figure below B, C is equal to AC is equal to 80 angle C aid is equal
to 40 degree angle.
It was the video.
Give it a try and then let's do it together.
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I hope you've given it a try.
It's given that B.S. is equal to Acey is equal to 80.
So let me market like this now, because these two sides are equal.
We know that isosceles triangle.
If two sides are equal, the angles opposite the equal sides are also equal.
Right.
Therefore, these two angles are equal.
Now, over here we have this side equal to this side.
Therefore, these two and both are also equal.
Now it's given that angle C, it is equal to forty degrees.
Right now I can say that 40 plus X plus X is equal to 180 degrees as per the angles and property of
a triangle.
Therefore X is equal to 70 degree.
Right, 180 minus 40 gives you one forty one forty by two.
Gives you seventy degrees.
All right.
We have X as 70 degrees now x this angle over here is an external angle to triangle ABC.
Right.
Therefore, I can say that X is equal to Z plus and that's to Z.
As for the exterior angle property of a triangle, therefore that is equal to 70 by two or X by two,
which gives you thirty five degrees right now.
Over here you can see that plus forty plus angle E it is equal to 180 degrees.
Right.
Why is that so.
Because that's equal to this angle, which is a straight angle and the straight angle is equal to 180
degrees.
Therefore substituting the values for that we have thirty five plus forty plus.
It is equal to 180 degree or angle, it is equal to one hundred and five degrees, which is your answer.