Help please what is the measure

Is δ pmr similar to δ smn ? if so, which postulate or theorem proves these two triangles are similar?

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?

What is the solution to the equation? k/6.4=8.7 2.3 5.568 15.1 55.68