First choose a coordinate system:
I'll take N as +y and E as +x.
Now resolve each vector into components in this coordinate system. ( is the angle between the vector and the +x axis.)
Now, add the x components together to form the x component of the resultant and add the y components together to form the y component of the resultant .
I recommend drawing a sketch at this point, but note that both components of R are positive. Thus R is a vector in Quadrant I. So to find the length and the angle:
(Note: Finding using the absolute value bars gives the reference angle, from which you can extract the angle if you know what quadrant it is in.)
So A + B is 11 m at 78 degrees above the + x axis, otherwise known as 78 degrees N of E.