Determine the fourth proportional to 9.6 m 7.2 m 28.8 m.

Options

A. 22.6 m
B. 21.6 m
C. 23.6 m
D. 20.6 m

Answer

To determine the fourth proportional to the numbers 9.6 m, 7.2 m, and 28.8 m, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Proportional Relationship**:
We want to find the fourth proportional \( x \) such that:
\[ \frac{9.6}{7.2} = \frac{28.8}{x} \]

2. **Cross-Multiplying**:
To solve for \( x \), we can cross-multiply:
\[ 9.6 \times x = 28.8 \times 7.2 \]

3. **Calculating the Right Side**:
Next, we calculate \( 28.8 \times 7.2 \):
\[ 28.8 \times 7.2 = 207.36 \]

4. **Setting Up the Equation**:
Now we can set up the equation:
\[ 9.6x = 207.36 \]

5. **Solving for \( x \)**:
To find \( x \), divide both sides by 9.6:
\[ x = \frac{207.36}{9.6} \]

6. **Calculating \( x \)**:
Performing the division:
\[ x = 21.6 \]

### Final Answer:
The fourth proportional to 9.6 m, 7.2 m, and 28.8 m is \( \boxed{21.6} \).

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