A proportion looks like this:

It means that the quantity a,b,c and d are in the same proportion: the ratio between a and b is the same ratio between c and d.
They are particularly useful in situation when you have an example given, and you want to extrapolate the relationship for another couple.
For example, you can think of the following problem: "Five apples cost 2 dollars. How much will 8 apples cost?"
You can build the proportion

And then solve it for x:

Should be 7.5% I have to add more words to this sentence to post it
Answer:
1.5326
Step-by-step explanation:
there is no more simplification it can only be calculated by a calculator
Answer:
An exponent value in a would make the system inconsistent because it will either gain or lose height over time.
Any real number without an exponent value will make the system consitent.
Any infintite/repeating number will make the system both consistent and inconsistent. it is consisent because it will stay at a constant rate but also inconsistent because it is repeating and will never end.