Answer: 15
Step-by-step explanation:
Opposite angles of a cyclic quadrilateral are supplementary, so:

Answer:
b, c, a
Step-by-step explanation:
The total number of marbles is 30+20+50= 100, so. Since there are 20 red marbles and 50 blue marbles. There are 30+50=80. 80/100=4/5= 80%
Glass and Titanium. Glass is because (10,40) (y over x) is 4 and Titanium is because (10,60) is 6 cork and lead are not since when dividing y over x it doesn't equal 2.