Finding the Fourth Proportional to 30,789.81, 42,490.31 and 18,686.79

Step by Step Solution

1. Step 1: Write the proportion equation
   30,789.81 : 42,490.31 = 18,686.79 : x
2. Step 2: Convert to fraction form
   30,789.81/42,490.31 = 18,686.79/x
3. Step 3: Cross multiply
   30,789.81x = 42,490.31 × 18,686.79
4. Step 4: Simplify right side
   30,789.81x = 794,007,500.00
5. Step 5: Solve for x
   x = 794,007,500.00/30,789.81
6. Step 6: Final answer
   x = 25,788.00