Finding the Fourth Proportional to 103,818.10, 155,399.10 and 81,510.70

Step by Step Solution

1. Step 1: Write the proportion equation
   103,818.10 : 155,399.10 = 81,510.70 : x
2. Step 2: Convert to fraction form
   103,818.10/155,399.10 = 81,510.70/x
3. Step 3: Cross multiply
   103,818.10x = 155,399.10 × 81,510.70
4. Step 4: Simplify right side
   103,818.10x = 12,666,689,420.37
5. Step 5: Solve for x
   x = 12,666,689,420.37/103,818.10
6. Step 6: Final answer
   x = 122,008.49