Answer:
Explanation:
There are two rows of numbers around the edge of the protractor.
You can see that BC is lying over two numbers: 0 in the inner row of numbers, and 180 in the outer row.
You want to start counting from 0, so use the inner row of numbers.
Now find arrow BA. It is lying between the 130 and 140 in the inner row, so the angle is 135°.
(BA is also lying between 40 and 50, but they're part of the outer row, so pretend you don't see them.)
Just remember to start with 0°. If arrow AB had been lying over the 0, you would start counting from there. In the attached example, you would use the outer row of numbers. It still gets you to 135°.