Finding the Fourth Proportional to 139,828.72, 209,773.80 and 102,780.40

Step by Step Solution

1. Step 1: Write the proportion equation
   139,828.72 : 209,773.80 = 102,780.40 : x
2. Step 2: Convert to fraction form
   139,828.72/209,773.80 = 102,780.40/x
3. Step 3: Cross multiply
   139,828.72x = 209,773.80 × 102,780.40
4. Step 4: Simplify right side
   139,828.72x = 21,560,635,073.52
5. Step 5: Solve for x
   x = 21,560,635,073.52/139,828.72
6. Step 6: Final answer
   x = 154,193.18