Are you sure your in high school, also it's answer #3.
It would be: 12/15 = 4/5
In short, Your Answer would be 4/5
Hope this helps!
I believe the answer is c, TSR
Answer:
Step-by-step explanation:
Angles a and b are opposite, so they are equal. The same is true for angles O and 3b.
So, the four angles are actually (starting from the left and going clockwise) 3b,b,3b,b
These four angles sum up to 360, so we have

And since a and b were the same, a is also 45 degrees.