Finding the Fourth Proportional to 7,978.67, 11,007.60 and 7,966.37

Step by Step Solution

1. Step 1: Write the proportion equation
   7,978.67 : 11,007.60 = 7,966.37 : x
2. Step 2: Convert to fraction form
   7,978.67/11,007.60 = 7,966.37/x
3. Step 3: Cross multiply
   7,978.67x = 11,007.60 × 7,966.37
4. Step 4: Simplify right side
   7,978.67x = 87,690,612.06
5. Step 5: Solve for x
   x = 87,690,612.06/7,978.67
6. Step 6: Final answer
   x = 10,990.62