What is the fourth proportional to 15, 12, and 20.

Options

A. 14
B. 12
C. 18
D. 16

Answer

To find the fourth proportional to the numbers 15, 12, and 20, we can use the formula for the fourth proportional. The fourth proportional (let's denote it as \( x \)) can be calculated using the relationship:

\[ \frac{a}{b} = \frac{c}{x} \]

Where:
- \( a = 15 \)
- \( b = 12 \)
- \( c = 20 \)

Rearranging the formula gives us:

\[ x = \frac{b \cdot c}{a} \]

Now, substituting the values into the formula:

\[ x = \frac{12 \cdot 20}{15} \]

Calculating the numerator:

\[ 12 \cdot 20 = 240 \]

Now, substituting back into the equation for \( x \):

\[ x = \frac{240}{15} \]

Now, performing the division:

\[ 240 \div 15 = 16 \]

Thus, the fourth proportional to 15, 12, and 20 is:

\[ \boxed{16} \]