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.
Step-by-step explanation: since the violin was 50 % off, that just means that the price it is is half of what it normally was , so you just multiple the fifty by 2 to get your answer which is that the violin cost 100$
