Finding the Fourth Proportional to 5,699.90, 7,871.29 and 5,389.28

Step by Step Solution

1. Step 1: Write the proportion equation
   5,699.90 : 7,871.29 = 5,389.28 : x
2. Step 2: Convert to fraction form
   5,699.90/7,871.29 = 5,389.28/x
3. Step 3: Cross multiply
   5,699.90x = 7,871.29 × 5,389.28
4. Step 4: Simplify right side
   5,699.90x = 42,420,585.77
5. Step 5: Solve for x
   x = 42,420,585.77/5,699.90
6. Step 6: Final answer
   x = 7,442.35