Find cos(a) in the triangle

Listed in the table is the percentage of students who chose each kind of juice at lunchtime. use the table to determine the measure of the central angle you would draw to represent orange juice in a circle graph

Write an algebraic expression for the word expression the quotient of c and 8

What is the answer to this question? i'm a bit stumped. also how do i do it? 5(x - 4) = 2(x + 5)