Finding the Fourth Proportional to 5,209.31, 7,188.85 and 2,851.61

Step by Step Solution

1. Step 1: Write the proportion equation
   5,209.31 : 7,188.85 = 2,851.61 : x
2. Step 2: Convert to fraction form
   5,209.31/7,188.85 = 2,851.61/x
3. Step 3: Cross multiply
   5,209.31x = 7,188.85 × 2,851.61
4. Step 4: Simplify right side
   5,209.31x = 20,499,764.17
5. Step 5: Solve for x
   x = 20,499,764.17/5,209.31
6. Step 6: Final answer
   x = 3,935.21