Finding the Fourth Proportional to 72,978.30, 109,467.72 and 20,387.70

Step by Step Solution

1. Step 1: Write the proportion equation
   72,978.30 : 109,467.72 = 20,387.70 : x
2. Step 2: Convert to fraction form
   72,978.30/109,467.72 = 20,387.70/x
3. Step 3: Cross multiply
   72,978.30x = 109,467.72 × 20,387.70
4. Step 4: Simplify right side
   72,978.30x = 2,231,795,035.04
5. Step 5: Solve for x
   x = 2,231,795,035.04/72,978.30
6. Step 6: Final answer
   x = 30,581.63