HELP PLS SHOW WORK ITS 2 PARTS

Cassie is traveling 675 miles today to visit her brother and his family. so far, she has stopped for gas three times. at the first stop, she put in 7.1 gallons of gas and paid $23.79. at her second stop, she put in 5.8 gallons of gas and paid $19.08. and, at the third stop, 6.6 gallons and paid $20.39. at which stop did casey pay the most for gas?

Whats the name of the vertical axis

Which statement is true? n is a point of tangency on circle p. pt is a secant of circle p. is a secant of circle p. vu is a tangent of circle p.