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# Could I have some help pls watch

1. I have the answer but I wondered why they needed to sate 'Angle PBA + Angle APB = 3x+40'?
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5. They just added that because they want to show you what they did to get the 3x+40. You could just show you added the angles but they just wrote it in that way.
6. I haven't looked at properly but I think its because angles in a triangle add up-to to 180 degrees right?
So those two angles in the triangle plus the last angle in triangle adds up to 180.
So to find the last angle you would do 3x+40-180= (the last angle in triangle)
angles on a straight line add up-to to 180 degrees and the last angle in triangle lies on a straight line (along with the angle outside the triangle)

So do the last angle in the triangle - 180 to find the angle outside the triangle

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Updated: February 15, 2018
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