A proton initially has v40 i -20 j 30 k and then 4 seconds

Question

Solve the all parts of given question:

Question: A proton initially has V=4.0 i -2.0 j +3.0 k and then 4 seconds later has v= -2.0 i -2.0 j +5.0 k (in meters per second).

Part A: For those 4 seconds, what is the protons average acceleration in unit vector notation?

Part B: What is the proton's average acceleration in magnitude?

Part C: Find the angle between the average acceleration vector and the positive direction of the x-axis?

I need help to determine the proton's average acceleration in magnitude.