Finding the Fourth Proportional to 9,123.78, 12,591.06 and 5,144.65

Step by Step Solution

1. Step 1: Write the proportion equation
   9,123.78 : 12,591.06 = 5,144.65 : x
2. Step 2: Convert to fraction form
   9,123.78/12,591.06 = 5,144.65/x
3. Step 3: Cross multiply
   9,123.78x = 12,591.06 × 5,144.65
4. Step 4: Simplify right side
   9,123.78x = 64,776,596.83
5. Step 5: Solve for x
   x = 64,776,596.83/9,123.78
6. Step 6: Final answer
   x = 7,099.75