Finding the Fourth Proportional to 72,728.71, 109,092.88 and 20,138.02

Step by Step Solution

1. Step 1: Write the proportion equation
   72,728.71 : 109,092.88 = 20,138.02 : x
2. Step 2: Convert to fraction form
   72,728.71/109,092.88 = 20,138.02/x
3. Step 3: Cross multiply
   72,728.71x = 109,092.88 × 20,138.02
4. Step 4: Simplify right side
   72,728.71x = 2,196,914,599.30
5. Step 5: Solve for x
   x = 2,196,914,599.30/72,728.71
6. Step 6: Final answer
   x = 30,206.98