Someone explain how to solve this on Jupyter notebook please. Im very lost. Thanks!

Given a triangle with vertices at the coordinates A(2, 4), B(1, -2), C(3, 7): (a) Find the lengths of the sides. (b) Use the Law of Cosines formula to find cos(ZBAC). NOTE the formula can be rewritten as b2 + c2-a2 cos(ZBAC) 2bc where a, b, c are BC, AC, AB respectively. (c) Confirm your answer by finding cos(ZBAC) by using the dot product for- mula to find the angle between a = AB = (1, -6) and b = A = (1, 3). NOTE that you found the magnitudes in part (a), and you can compute the dot product by just using arithmetic operations