In an equilateral triangle each interior angle is trisected by a pair of rays. The intersection of the interiors of the middle 20°-angle at each vertex is the interior of a convex hexagon. What is the degree measure of the smallest angle of this hexagon?
(A)80(B)90(C)100(D)110(E)120
∠ADE is the exterior angle of △ABD. ∠ADE=60+20=80
∠AFC is the exterior angle of △DFC. ∠AFC=80+20=100
For △BNC: ∠N=180−20−20=140 Therefore, the angles of the hexagon are 100 and 140 alternately.
