Finding the Fourth Proportional to 21,785.61, 30,062.39 and 12,355.05

Step by Step Solution

1. Step 1: Write the proportion equation
   21,785.61 : 30,062.39 = 12,355.05 : x
2. Step 2: Convert to fraction form
   21,785.61/30,062.39 = 12,355.05/x
3. Step 3: Cross multiply
   21,785.61x = 30,062.39 × 12,355.05
4. Step 4: Simplify right side
   21,785.61x = 371,422,269.79
5. Step 5: Solve for x
   x = 371,422,269.79/21,785.61
6. Step 6: Final answer
   x = 17,048.97