Finding the Fourth Proportional to 9,321.85, 12,859.31 and 5,778.91

Step by Step Solution

1. Step 1: Write the proportion equation
   9,321.85 : 12,859.31 = 5,778.91 : x
2. Step 2: Convert to fraction form
   9,321.85/12,859.31 = 5,778.91/x
3. Step 3: Cross multiply
   9,321.85x = 12,859.31 × 5,778.91
4. Step 4: Simplify right side
   9,321.85x = 74,312,734.11
5. Step 5: Solve for x
   x = 74,312,734.11/9,321.85
6. Step 6: Final answer
   x = 7,971.89