A yard is equal in length to three feet. The function [tex]f(x)[/tex] takes a measurement in yards (as input) and returns a measurement in feet (as output).

[tex]f(x) = 3x[/tex]

\[
\begin{array}{cl}
\text{Input:} & \text{Output} \\
\text{Yards} & \text{Feet} \\
1 & \longrightarrow f(1) = 3 \\
2 & \longrightarrow f(2) = 6 \\
12.2 & \longrightarrow f(12.2)
\end{array}
\]

What number will the function return if the input is [tex]12.2[/tex]?

A. 36.6
B. 36.2
C. 14.2
D. 15.2

To solve the problem of converting 12.2 yards to feet using the function [tex]$ f(x) = 3x $[/tex], follow these steps:

1. Understand the function: The function [tex]$ f(x) = 3x $[/tex] takes a measurement in yards and converts it to feet. Since 1 yard is equal to 3 feet, multiplying the yards by 3 gives you the equivalent feet.

2. Input the given value: We need to find the function's output when the input is 12.2 yards. This means we substitute [tex]$ x $[/tex] with 12.2 in the function.

3. Perform the calculation:
- Using the formula [tex]$ f(x) = 3x $[/tex]:
- Substitute [tex]$ x = 12.2 $[/tex]:
- Calculate [tex]$ f(12.2) = 3 \times 12.2 $[/tex].

4. Calculate the product: Multiply 12.2 by 3:
- [tex]$ 3 \times 12.2 = 36.6 $[/tex].

Therefore, the function will return 36.6 when the input is 12.2 yards.

So, the choice is:
A. 36.6