Hoo pleas i want to undertsand

High schoolmathematics 5 points keith is the leading goal scorer for a team in an ice hockey league. last season, he scored 42 goals in 82 games. assuming he scores goals at a constant rate, what is the slope of the line that represents this relationship if the number of games is along the x-axis and the number of goals is along the y-axis?

Don't know how to find x given these segment lengths

Ab based on the given diagram, if m_1 = 60° then m 2 = 30 60 90 180