Please help​

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

Answer asap and if you do you will get brainliest. catherine buys a gallon of ice cream from the store. after taking it home, she eats a fifth of a gallon of ice cream. her sister eats some of the ice cream as well. if two-thirds of the original amount of ice cream is left, then what fraction of a gallon of ice cream did her sister eat?

X² + 4y² = 36 the major axis runs along: a) y=4x b) x-axis c) y-axis