Pls help 10 less than 17 !

Which is a true statement about an exterior angle of a triangle a. it is formed by two segments that are not sides of the triangle, b. it forms a linear pair with one of the interior angles of the triangle, c. it is complementary to one of the interior angles of the triangle. d. it is formed by two segments that are sides of the triangle.

What is the difference between the predicted value and the actual value

Find the area of the regular hexagon if a side is 20 cm.