Hel 20 point if you get all right

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.

Explain how you can use the associative property to evaluate (7x50)x4.

Explain how you can find the missing fraction in 3 4/5 / (blank) 2 5/7. then find the missing fraction.