4/5+×=13/5 how do i solve this problem

Find the value of the cosine for angle a

Players on the school soccer team are selling candles to raise money for an upcoming trip. each player has 24 candles to sell. if a player sells 4 candles a profit of$30 is made. if he sells 12 candles a profit of $70 is made. determine an equation to model his situation?

The reflexive property of congruence lets you say that ∠pqr ≅