Given :-
Measure of an angle = x
Measure of another angle = x - 143.4
Each angle is the supplement of the other angle .
Which means :-






Then :-
Measure of the first angle :-

Measure of the second angle :-



As the sum of the measure of each angle adds up to 180° (161.7+18.3=180) , we can conclude that we have found out the correct value of each of the angles .
Therefore , the measure of the first angle is = 161.7° and the measure of it's supplementary angle is = 18.3° .