X is the amount of distilled water that must be added (in milliliters)
2/(100+x)=9/(1000)
2000=900+9x
1100=9x
122.22=x
x= 122
The answer is 122 milliliters of distilled water must be added
Not sure why such an old question is showing up on my feed...
Anyway, let

and

. Then we want to find the exact value of

.
Use the angle difference identity:

and right away we find

. By the Pythagorean theorem, we also find

. (Actually, this could potentially be negative, but let's assume all angles are in the first quadrant for convenience.)
Meanwhile, if

, then (by Pythagorean theorem)

, so

. And from this,

.
So,
♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️


Inverse both sides

Multiply sides by 4



Subtract sides 8


Done...
♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️
I believe the answer is b because u need to combine like terms and 6c+2c+5c is 13c.
They are opposite exterior angles