Finding the Fourth Proportional to 2,605,686,128.10, 3,909,096,062.55 and 858,591,555.30

Step by Step Solution

1. Step 1: Write the proportion equation
   2,605,686,128.10 : 3,909,096,062.55 = 858,591,555.30 : x
2. Step 2: Convert to fraction form
   2,605,686,128.10/3,909,096,062.55 = 858,591,555.30/x
3. Step 3: Cross multiply
   2,605,686,128.10x = 3,909,096,062.55 × 858,591,555.30
4. Step 4: Simplify right side
   2,605,686,128.10x = 3,356,316,868,161,910,784
5. Step 5: Solve for x
   x = 3,356,316,868,161,910,784/2,605,686,128.10
6. Step 6: Final answer
   x = 1,288,074,120.66