Finding the Fourth Proportional to 12,390.29, 17,099.10 and 7,085.10

Step by Step Solution

1. Step 1: Write the proportion equation
   12,390.29 : 17,099.10 = 7,085.10 : x
2. Step 2: Convert to fraction form
   12,390.29/17,099.10 = 7,085.10/x
3. Step 3: Cross multiply
   12,390.29x = 17,099.10 × 7,085.10
4. Step 4: Simplify right side
   12,390.29x = 121,148,833.41
5. Step 5: Solve for x
   x = 121,148,833.41/12,390.29
6. Step 6: Final answer
   x = 9,777.73