Could use some help thanks

1. Use the dot product to find the four interior angles of the parallelogram made by the points (0, 0), (6, 0), (8, 3), (2, 3) (you may use geometry arguments to get the other angles after calculating at least one angle with the dot product). 2. For what value of an are the vectors a1, 4, 2] and [4, -1, 10] orthogonal? 3. Find all unit vectors a = a1, a2 in the plane orthogonal to the vec- tor 4, 3 . (Hint: use the dot product, but consider drawing yourself a picture. That will help you find all the answers) 4. For a = 8, 2, 0 and b = [-4, -1, 0 , find the projection of a in the direction of b