Efficiently Calculate Radian Circles | Part B Explanation

[synkk]

for part b I'm not sure how to do it

any hints on how to do it? I've tried using sine rule etc but I'm just guessing, and I'm pretty sure there is a more simple method.

 

[Ninty64]

Hint: What is the relation between the angles DAB and DAC?

 

[synkk]

Hint: What is the relation between the angles DAB and DAC?

Right well I got this, I'm not sure if its right. DAB and DAC are equal so let's call DAB "a", 2pi = 2.2 + 2a so 2pi - 2.2 / 2 = a which is pi - 1.1 = 2.04?

 

[Ninty64]

That's right, and I believe your math is correct too.

Since all three sides of the triangles are congruent:
\overline{DB}\cong\overline{DC} given
\overline{BA}\cong\overline{AC} because they are the same length
\overline{AD}\cong\overline{AD} trivial, they share a common line
Then the corresponding angles in the triangles must also be congruent.