Finding the Fourth Proportional to 1,389,825,209.20, 2,085,090,684.72 and 643,379,123.92

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389,825,209.20 : 2,085,090,684.72 = 643,379,123.92 : x
2. Step 2: Convert to fraction form
   1,389,825,209.20/2,085,090,684.72 = 643,379,123.92/x
3. Step 3: Cross multiply
   1,389,825,209.20x = 2,085,090,684.72 × 643,379,123.92
4. Step 4: Simplify right side
   1,389,825,209.20x = 1,341,503,818,028,906,496
5. Step 5: Solve for x
   x = 1,341,503,818,028,906,496/1,389,825,209.20
6. Step 6: Final answer
   x = 965,232,037.20