Finding the Fourth Proportional to 12,978, 19,480.86 and 5,586.12

Step by Step Solution

1. Step 1: Write the proportion equation
   12,978 : 19,480.86 = 5,586.12 : x
2. Step 2: Convert to fraction form
   12,978/19,480.86 = 5,586.12/x
3. Step 3: Cross multiply
   12,978x = 19,480.86 × 5,586.12
4. Step 4: Simplify right side
   12,978x = 108,822,421.66
5. Step 5: Solve for x
   x = 108,822,421.66/12,978
6. Step 6: Final answer
   x = 8,385.15