The measure of angle 1 is 210 degrees.
You'll have to draw an auxiliary line in between the two parallel lines.
Then, you'll have to find out the angle measures next to 100 and next to 50. Since a line is 180°, then the angle measures next to 100 and 50 are 80 and 130 respectively.
Then, since you have an auxiliary line, you can use the rule of alternate interior angles of parallel lines being equal.
Then from there just add up 80 and 130 to get you 210.
