Finding the Fourth Proportional to 10,000.78, 13,799.89 and 5,524.31

Step by Step Solution

1. Step 1: Write the proportion equation
   10,000.78 : 13,799.89 = 5,524.31 : x
2. Step 2: Convert to fraction form
   10,000.78/13,799.89 = 5,524.31/x
3. Step 3: Cross multiply
   10,000.78x = 13,799.89 × 5,524.31
4. Step 4: Simplify right side
   10,000.78x = 76,234,870.33
5. Step 5: Solve for x
   x = 76,234,870.33/10,000.78
6. Step 6: Final answer
   x = 7,622.89