Finding the Fourth Proportional to 12,789, 17,643.96 and 9,439.92

Step by Step Solution

1. Step 1: Write the proportion equation
   12,789 : 17,643.96 = 9,439.92 : x
2. Step 2: Convert to fraction form
   12,789/17,643.96 = 9,439.92/x
3. Step 3: Cross multiply
   12,789x = 17,643.96 × 9,439.92
4. Step 4: Simplify right side
   12,789x = 166,557,570.88
5. Step 5: Solve for x
   x = 166,557,570.88/12,789
6. Step 6: Final answer
   x = 13,023.50