A_{1}: (50, 7.6)
A_{2}: (100, 7.4)
A_{3}: (200, 6.9)
A_{4}: (300, 6.5)
A_{5}: (400, 6.2)
A_{6}: (500, 5.9)
A_{7}: (600, 5.7)
A_{8}: (700, 5.4)
f = Line(A_{1}, A_{2})