Both lines are parallel so using the bottom line you are given angle 7 as being 80 degrees. Angle 5 and 7 form a straight line which is 180 degrees so angle 5 would be 180-80 = 100 degrees.
Angle 1 is the same as angle 5 so angle 1 is 100 degrees.
Answer: 100 degrees
Answer to your problem is:
1 411/500
I believe XD.
A is 23 and the answer to b is 77
About 3,000 books because 105 * 28 = 2940
and 2940 rounded to the nearest thousand is 3000. Hope this helps.
