Finding the Fourth Proportional to 12,985.35, 17,920.31 and 7,320.31

Step by Step Solution

1. Step 1: Write the proportion equation
   12,985.35 : 17,920.31 = 7,320.31 : x
2. Step 2: Convert to fraction form
   12,985.35/17,920.31 = 7,320.31/x
3. Step 3: Cross multiply
   12,985.35x = 17,920.31 × 7,320.31
4. Step 4: Simplify right side
   12,985.35x = 131,182,143.09
5. Step 5: Solve for x
   x = 131,182,143.09/12,985.35
6. Step 6: Final answer
   x = 10,102.32