Understanding the Problem
To determine how much we need to multiply 0.15 to achieve 2.25, we need to set up an equation. Let's denote the multiplier as \( x \). The equation can be represented as:
\[
0.15 \times x = 2.25
\]

Solving for the Multiplier
To find \( x \), we will rearrange the equation:
1. Divide both sides by 0.15:
\[
x = \frac{2.25}{0.15}
\]
2. Now, let's perform the division:
- Convert 2.25 and 0.15 into simpler fractions or decimals for easier calculation.
- 2.25 can be expressed as \( \frac{225}{100} \) or simply 2.25.
- 0.15 can be expressed as \( \frac{15}{100} \).
3. Now, substituting back into the equation:
\[
x = \frac{2.25}{0.15} = \frac{225}{15}
\]
4. This simplifies to:
\[
x = 15
\]

Conclusion
Thus, you need to multiply 0.15 by **15** to get 2.25.

Verification
To verify:
- Multiply:
\[
0.15 \times 15 = 2.25
\]
This confirms that the calculation is correct. Therefore, the answer is **15**.

15