Finding the Fourth Proportional to 7,165.76, 9,887.55 and 3,978.54

Step by Step Solution

1. Step 1: Write the proportion equation
   7,165.76 : 9,887.55 = 3,978.54 : x
2. Step 2: Convert to fraction form
   7,165.76/9,887.55 = 3,978.54/x
3. Step 3: Cross multiply
   7,165.76x = 9,887.55 × 3,978.54
4. Step 4: Simplify right side
   7,165.76x = 39,338,013.18
5. Step 5: Solve for x
   x = 39,338,013.18/7,165.76
6. Step 6: Final answer
   x = 5,489.72