Answer:
Rational
Step-by-step explanation:
A rational number can be written as a fraction of the form.

and a and b are integers.

Hence in this case a=999 and b=100.
Since both are integers with b being a non-zero integer, we conclude that 9.99 is a rational number.
The formula for findong the area of a circle is

Using that formula, you would do pi(9). After that, multiply pi by 9 and you would get ~28.274. Hope this helps!
I believe it’s c. I hope that this is helpful!
Answer:
19
Step-by-step explanation:
Answer:
B) y = 9 x has Proportionality Constant = 9
Step-by-step explanation:
Two quantities P and Q are said to be PROPORTIONAL if and only if:
P ∝ Q ⇔ P = k Q ⇔ 
Here, k = PROPORTIONALITY CONSTANT
Given : k = 9
Now, let us consider the given expressions in which x ∝y
y = 81/3 x
Here, 
So, here Proportionality Constant ≠ 9
y = 9 x
Here, 
So, here Proportionality Constant = 9
y = 3 x
Here, 
So, here Proportionality Constant ≠ 9
y = 1/9 x
Here, 
So, here Proportionality Constant ≠ 9
Hence, only y = 9 x has Proportionality Constant = 9