The question reminds you of all the tools you need:
It says ...
"Opposite angles are equal."
So the upper right angle is x+40 just like the bottom left,
and the bottom right angle is 3x+20 just like the upper left.
And it says ...
"The sum of all angles is 360°."
You know what each of the four angles is, so you can addum all up,
set the sum equal to 360, find out what number ' x ' is, and then
use that to find the size of every angle.
8b - 1 = 24b + 4
8b - 1 + 1 = 24b + 4 + 1
8b = 24b + 5
8b - 24b = + 5
-16 = + 5
-5/16
Answer: b = -5/16
Median = 70.
If you arrange all the numbers in ascending order, 70 will be the middle number.
I apologise, but it is as though that there is some missing necessary information. Perhaps there was an error?