Vectors t = -5i + 2], u = -3i + 7], and v = 8i + 20] are given. Part A: Find the angle between vectors t and u. Show all necessary calculations. (5 points) Part B: Choose a value for c, such that c > 'I. Find w = CV. Show all necessary work. (2 points) Part C: Use the dot product to determine ift and w are parallel, orthogonal, or neither. Justify your answer. (3 points)