Which relationship has a zero slope?

Me write an equation for the interior angles of this triangle that uses the triangle sum theorem

Which of the following are parts of a sphere

Hector and alex traded video games. alex gave hector one fourth of his video games in exchange for 6 video games. then he sold 3 video games and gave 2 video games to his brother. alex ended up with 16 video games. how many video games did alex have when he started?