The scale on the map is 1 in = 13.5 units
135/10 = 13.5
Here we have a system of equation like this:

from the first equation we get:

Substitute in the second equation we get:

Substitute i the first equation again we get:

We deduce that:

A is bigger than B.
Half of a circle
1 circle=360
1/2 circle=360/2=180
1/2 circle cut into 1/3
180 times 1/3=60
60 degreees