Finding the Fourth Proportional to 400,784, 601,268.16 and 138,128

Step by Step Solution

1. Step 1: Write the proportion equation
   400,784 : 601,268.16 = 138,128 : x
2. Step 2: Convert to fraction form
   400,784/601,268.16 = 138,128/x
3. Step 3: Cross multiply
   400,784x = 601,268.16 × 138,128
4. Step 4: Simplify right side
   400,784x = 83,051,968,404.48
5. Step 5: Solve for x
   x = 83,051,968,404.48/400,784
6. Step 6: Final answer
   x = 207,223.76