Ok hello there Zoey! So when classifying what type of degree it should be put under, you need to know that straight lines have a degree of 180, right lines have a degree of 90, acute lines have a degree of less than 90, and finally, obtuse lines have a degree of more than 90 degrees. Knowing this information, you should know it's not a right line or acute line because 124 degrees is bigger than 90 degrees, but less than 180 degrees. So the classification for this line that has a degree of 124 is an obtuse line. For question 2 what complement means, is that it must equal to 90 degrees. So since we already have 72 degrees, subtract that from 90 to get 18 which is then B. Hope this helped, if you have a question, please ask!