Agirl delivering newspapers travels 1 blocks west, 3 blocks north, then 4 blocks east. what is the magnitude of her resultant displacement? answer in units of blocks.

Well, determine the x and y components of the displacement. 
Vx = (-1) + 4 = 3 
Vy = 3 = 3 

Then use a^2 + b^2 = c^2. 
a^2 + b^2 = c^2 
c = sqrt(a^2 + b^2) 
c= sqrt((3)^2 + (3)^2) 
c = sqrt(9 + 9) 
c = sqrt(18) 
c =~ 4.2 blocks     Determine the angle using arctangent. 

arctan(3/3) = Theta 
Theta = 45 degrees north of east 

(by 'Theta', I mean the angle you are wishing to find) 

_Part 3_ 

Since distance is a scalar, simply add up all the distances. 

1 + 3 + 4 = 8 blocks