if we take 2100 to be the 100%, what is 273 off of it in percentage?

The graph is shown in the attached image.
question 3 = $150 because 50% is one half of 100% so 300/2 = 150
Triangle-A is not "unique".
All of its angles are equal (60° each), and all of its sides
have the same length, but that length can be anything ...
1 millimeter, 1 light-year ... anything.
Each of the other choices can only be 1 triangle.
For each one, we can find the size of every angle,
and we can also find the length of every side.
There is no whole number that is half of 11 but the half number is 5.5