Explanation:
1.angels on a straight line add up to 180degrees
2.when you see the signs at number 6 and 7 it means it is 90 degrees
EG. number 6.it will be 90degrees+29degrees=119degrees remember that all angles on a straight line add up to 180 degrees. to get angel xwy you will subtract 119 degrees from 180 degrees =xwy which is 61 degrees
