Finding the Fourth Proportional to 12,789, 17,656.90 and 9,799.28

Step by Step Solution

1. Step 1: Write the proportion equation
   12,789 : 17,656.90 = 9,799.28 : x
2. Step 2: Convert to fraction form
   12,789/17,656.90 = 9,799.28/x
3. Step 3: Cross multiply
   12,789x = 17,656.90 × 9,799.28
4. Step 4: Simplify right side
   12,789x = 173,024,907.03
5. Step 5: Solve for x
   x = 173,024,907.03/12,789
6. Step 6: Final answer
   x = 13,529.20