Answer:
<BAC = 20°
Explanation:
It is given in the question that all 9 triangle which are formed are congruent, which means that in all triangles, the angle which is formed at point A is same.
Which means 9 angles collectively can be written as 9 · <BAC
If we consider all the 9 triangles, we can see in the figure that it forms a semicircle.
A semicircle has a total sum of angles equal to 180°
So we can write that:
9 · <BAC = 180°
Simplify for <BAC
<BAC = 20°