Finding the Fourth Proportional to 9,345.76, 14,002.78 and 5,640.21

Step by Step Solution

1. Step 1: Write the proportion equation
   9,345.76 : 14,002.78 = 5,640.21 : x
2. Step 2: Convert to fraction form
   9,345.76/14,002.78 = 5,640.21/x
3. Step 3: Cross multiply
   9,345.76x = 14,002.78 × 5,640.21
4. Step 4: Simplify right side
   9,345.76x = 78,978,556.58
5. Step 5: Solve for x
   x = 78,978,556.58/9,345.76
6. Step 6: Final answer
   x = 8,450.73