Finding the Fourth Proportional to 19,978.96, 27,564.38 and 12,909.54

Step by Step Solution

1. Step 1: Write the proportion equation
   19,978.96 : 27,564.38 = 12,909.54 : x
2. Step 2: Convert to fraction form
   19,978.96/27,564.38 = 12,909.54/x
3. Step 3: Cross multiply
   19,978.96x = 27,564.38 × 12,909.54
4. Step 4: Simplify right side
   19,978.96x = 355,843,466.19
5. Step 5: Solve for x
   x = 355,843,466.19/19,978.96
6. Step 6: Final answer
   x = 17,810.91