Finding the Fourth Proportional to 256,899.39, 385,385.98 and 79,420.23

Step by Step Solution

1. Step 1: Write the proportion equation
   256,899.39 : 385,385.98 = 79,420.23 : x
2. Step 2: Convert to fraction form
   256,899.39/385,385.98 = 79,420.23/x
3. Step 3: Cross multiply
   256,899.39x = 385,385.98 × 79,420.23
4. Step 4: Simplify right side
   256,899.39x = 30,607,443,170.38
5. Step 5: Solve for x
   x = 30,607,443,170.38/256,899.39
6. Step 6: Final answer
   x = 119,141.75