Helpp ill mark u as brainlist

Asquare parking lot has 6,400 square meters what is the length in meters

Mrs. morton has a special reward system for her class. when all her students behave well, she rewards them by putting 3 marbles into a marble jar. when the jar has 100 or more marbles, the students have a party. right now, the the jar has 24 marbles. how could mrs. morton reward the class in order for the students to have a party?

Solve the equation x/4 - 5= -8 -27 -12 -7 12