If you draw all of the diagonals from a single vertex of a convex polygon with 8 sides, how many triangles are formed? - 533480. ... 2. Added and checked by experts ... of sides 8-2= 6triangles ... Day, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31.