Finding the Fourth Proportional to 8,978.40, 13,465.76 and 5,645.12

Step by Step Solution

1. Step 1: Write the proportion equation
   8,978.40 : 13,465.76 = 5,645.12 : x
2. Step 2: Convert to fraction form
   8,978.40/13,465.76 = 5,645.12/x
3. Step 3: Cross multiply
   8,978.40x = 13,465.76 × 5,645.12
4. Step 4: Simplify right side
   8,978.40x = 76,015,831.09
5. Step 5: Solve for x
   x = 76,015,831.09/8,978.40
6. Step 6: Final answer
   x = 8,466.52