HELP ME PLSSS IM STUCK

-67

Step-by-step explanation:

The first choice (12)

Step-by-step explanation:

i'm not 100% what the theory is but here is how I did it:

the angle D and 115% are supplementary which means they add up to 180.

115+x=180

x=65

so now that you know all the angle measures, you also know that all angles of a triangle add up to 180.

65+3x+19+5x=180

combine like terms:

8x+84=180

subtract 84 from both sides:

8x=96

divide by 8 on both sides

x=12