Finding the Fourth Proportional to 8,999.83, 12,415.92 and 5,640.35

Step by Step Solution

1. Step 1: Write the proportion equation
   8,999.83 : 12,415.92 = 5,640.35 : x
2. Step 2: Convert to fraction form
   8,999.83/12,415.92 = 5,640.35/x
3. Step 3: Cross multiply
   8,999.83x = 12,415.92 × 5,640.35
4. Step 4: Simplify right side
   8,999.83x = 70,030,134.37
5. Step 5: Solve for x
   x = 70,030,134.37/8,999.83
6. Step 6: Final answer
   x = 7,781.28