To find out what number 3.16 is 45% of, we can set up the equation \( 0.45 \times x = 3.16 \). Solving for \( x \) will give us the number we are looking for.
Step 1: Set Up the Equation
We start with the equation that represents the problem:
\[
0.45 \times x = 3.16
\]
where \( x \) is the number we want to find.
Step 2: Solve for \( x \)
To isolate \( x \), we divide both sides of the equation by \( 0.45 \):
\[
x = \frac{3.16}{0.45}
\]
Step 3: Calculate the Value of \( x \)
Performing the division gives us:
\[
x \approx 7.0222
\]
Rounding to four significant digits, we have:
\[
x \approx 7.022
\]
Final Answer
Thus, the number of which 3.16 is 45% is
\[
\boxed{x = 7.022}
\]