Finding the Fourth Proportional to 1,386,404.10, 2,079,606.15 and 639,908.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,386,404.10 : 2,079,606.15 = 639,908.10 : x
2. Step 2: Convert to fraction form
   1,386,404.10/2,079,606.15 = 639,908.10/x
3. Step 3: Cross multiply
   1,386,404.10x = 2,079,606.15 × 639,908.10
4. Step 4: Simplify right side
   1,386,404.10x = 1,330,756,820,194.82
5. Step 5: Solve for x
   x = 1,330,756,820,194.82/1,386,404.10
6. Step 6: Final answer
   x = 959,862.15