180 degrees
Do you understand the figure eight shape? They are two triangles, with both sides extending in opposite directions from each other. In this case, because the two triangles have a pair of interior angles that are opposite each other, and the sum of the interior angles is 180 degrees, the sum of the other two angles in each triangle is equal. According to this idea, by connecting the vertices of the two adjacent angles of the five-pointed star, you can "move" the two angles downward, so that the sum of the five angles is actually the sum of the interior angles of a triangle, which is 180 degrees.