Finding the Fourth Proportional to 13,138.79, 18,131.52 and 8,423.07

Step by Step Solution

1. Step 1: Write the proportion equation
   13,138.79 : 18,131.52 = 8,423.07 : x
2. Step 2: Convert to fraction form
   13,138.79/18,131.52 = 8,423.07/x
3. Step 3: Cross multiply
   13,138.79x = 18,131.52 × 8,423.07
4. Step 4: Simplify right side
   13,138.79x = 152,722,929.39
5. Step 5: Solve for x
   x = 152,722,929.39/13,138.79
6. Step 6: Final answer
   x = 11,623.82