Okay so whats the question?
Answer:
It's the law of cosines
Step-by-step explanation:
law of cosines states that 
so we know that a = 7, b = 4, and alpha would be 135 degrees, so just plugging it in gets us 49+16-2*7*4*(-0.707) = 65 + 39.59 = 104.59
Since there is 7 water bottles in a package and the total price is 5.60, you divide 7 by 5.60 which gives you 1.25 per bottle
Answer: Irrational because cannot be turned into fractions
Step-by-step explanation: