Finding the Fourth Proportional to 13,199.72, 18,215.56 and 7,231.38

Step by Step Solution

1. Step 1: Write the proportion equation
   13,199.72 : 18,215.56 = 7,231.38 : x
2. Step 2: Convert to fraction form
   13,199.72/18,215.56 = 7,231.38/x
3. Step 3: Cross multiply
   13,199.72x = 18,215.56 × 7,231.38
4. Step 4: Simplify right side
   13,199.72x = 131,723,636.27
5. Step 5: Solve for x
   x = 131,723,636.27/13,199.72
6. Step 6: Final answer
   x = 9,979.28