Finding the Fourth Proportional to 899,196.72, 1,240,876.80 and 491,289.78

Step by Step Solution

1. Step 1: Write the proportion equation
   899,196.72 : 1,240,876.80 = 491,289.78 : x
2. Step 2: Convert to fraction form
   899,196.72/1,240,876.80 = 491,289.78/x
3. Step 3: Cross multiply
   899,196.72x = 1,240,876.80 × 491,289.78
4. Step 4: Simplify right side
   899,196.72x = 609,630,090,079.10
5. Step 5: Solve for x
   x = 609,630,090,079.10/899,196.72
6. Step 6: Final answer
   x = 677,971.88