So if we call this angle right over here y we know that y plus x is going to be equal to 180 degrees and we know x is equal to 66 degrees, so this is 66 so we can subtract 66 from both sides and we get y is equal to 180-66 is 114 and that number n=might look a little familiar to you. notice this 114 is the exact same sum as these two angles over here.