P$4.$

a$)$ Write the relative position vector from $A$ to $B.$

b$)$ Find the unit vector from $A$ to $B.$

c$)$ Write the relative position vector from $A$ to $C.$

d$)$ Find the unit vector from $A$ to $C.$

e$)$ Calculate the angle $$ between the lines $AB$ and $AC.$

f$)$ Calculate the projection of vec$(F)$ onto the $AB$ line and express it in Cartesian vector form.

F$=220$i$-221$j$+151$k$($N$)$