The fourth proportional to 0.2 ,0.12 and 0.3 is

Options

A. 0.13
B. 0.15
C. 0.18
D. 0.8

Answer

To find the fourth proportional to the numbers 0.2, 0.12, and 0.3, we can use the property of proportions. The fourth proportional \( D \) can be found using the formula:

\[ \frac{A}{B} = \frac{C}{D} \]

Where:
- \( A = 0.2 \)
- \( B = 0.12 \)
- \( C = 0.3 \)
- \( D \) is the fourth proportional we need to find.

### Step 1: Set up the proportion
We can set up the equation as follows:

\[ \frac{0.2}{0.12} = \frac{0.3}{D} \]

### Step 2: Cross-multiply
Cross-multiplying gives us:

\[ 0.2 \cdot D = 0.3 \cdot 0.12 \]

### Step 3: Calculate the right side
Now calculate \( 0.3 \cdot 0.12 \):

\[ 0.3 \cdot 0.12 = 0.036 \]

### Step 4: Substitute back into the equation
Now substitute back into the equation:

\[ 0.2D = 0.036 \]

### Step 5: Solve for \( D \)
To find \( D \), divide both sides by \( 0.2 \):

\[ D = \frac{0.036}{0.2} \]

### Step 6: Perform the division
Now perform the division:

\[ D = 0.18 \]

### Conclusion
Thus, the fourth proportional to 0.2, 0.12, and 0.3 is \( \boxed{0.18} \).

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