Okay, I’m a little rusty on this type of math since it’s been over 5 years but I’ll give it a go. Angle 3 and 6 look like supplementary angles. This means both angles should add up to 180°. So, given the measure of angle 3 is 100°, subtract 180 from 100. You will get measure of angle 6=80. Can you give me the options for the second part of the question after “by the”?