just start of with the angles you know, for example angle 7 is 24° and then use angle laws for example angle 11 is 156° because it's a co-interior angle with angle 7 and co-interior angles add up to 180°.
that would then make angle 14 156° because they're vertically opposite angles. 13 and 12 would also be the same so
156+156=312°
360-312=48°
48/2=24°
13 and 12 are both 24°
if angle 20 is 80° that would make angle 10 100° as co-interior angles add up to 18° (as previously stated).
angles 10 and 13 add together to get 124°
180°( because all angles in a triangle add up to 180°) - 124° =56° so 16 is 56°.
that would make angle 17 124° as angles on a straight line add up to 180°.
does this help?