Two angles are said to be supplementary if their sum is 180 degrees. So, if x and y are supplementary angles, the formula is

We know that one of the angles (say x) is 98. So, the equation updates to

If we want to solve for the other angle, we can simply subtract 98 from both sides to get

The simplified version of that equation is

Sum of interior angles formula = (n-2) x 180
where n = number of sides
so,
( 19-2 ) x 180
= 17 x 180
= 3060
ans : A
hope it helps :)
Get her done ...........................
Answer: you got it right, it is the one that is blue highlighted.