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1. Just a quick revision question....

I have been doing some questions in the edexcel c2 book.

Chapter 6 - exercise 6c - qestion 1f.

The angle inside the triangle is 0.2 rad and it says that the angle outside the isosceles triangle (shaded bit) is therefore 0.4.

Can anyone please refresh my memory on why that is - went through circle theorem but nothing really helped...
2. (Original post by christinajane)
Just a quick revision question....

I have been doing some questions in the edexcel c2 book.

Chapter 6 - exercise 6c - qestion 1f.

The angle inside the triangle is 0.2 rad and it says that the angle outside the isosceles triangle (shaded bit) is therefore 0.4.

Can anyone please refresh my memory on why that is - went through circle theorem but nothing really helped...
https://0e90d90be05fe2865012661b731d...apter%2006.pdf
3. (Original post by christinajane)
Just a quick revision question....

I have been doing some questions in the edexcel c2 book.

Chapter 6 - exercise 6c - qestion 1f.

The angle inside the triangle is 0.2 rad and it says that the angle outside the isosceles triangle (shaded bit) is therefore 0.4.

Can anyone please refresh my memory on why that is - went through circle theorem but nothing really helped...
Is the first circle below the question?

If so, as it is an isosceles triangle (the two radii are equal in length), the angle at the top of the triangle is also 0.2radians.
Angles in a triangle add up to 180 degrees, which in radians, 180=pi.
Therefore the angle inside the triangle = pi - 0.2rad - 0.2rad = pi-0.4rad.
Angles on a straight line also add up to 180 degrees (pi) so the angle outside = pi-(pi-0.4rad) = pi-pi+0.4rad= 0.4rad

Hope that helps!
4. Ahhh yes thats the one!

Thank you very much I knew it would be something simple just couldn't connect the dots. Especially with this new measurement!

Im getting confused with all the pi!

I guess as well - when they leave the answer in pi form its similar to when you leave it in surd form?

Sometimes when Im doing the calculations I am also including the pi symbol and then the answer is wrong....Im not sure when to use pi and leave it out because just not used to pi and rads just yet!

Its a short chapter - but taking me all day to get through! :-(

So much for thinking it had something to do with circle theorems as well!

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