Answer:
a+b+c+d+e+f = 360º
Explanation:
Each side of the outer triangle
is a straight line segment which is 180º
Since there are three sides
180 * 3 = 540º
therefor a+b+c+d+e+f + inside triangle = 540
The angles of the inside triangle total 180º
a+b+c+d+e+f = 540 - 180
a+b+c+d+e+f = 360º