Finding the Fourth Proportional to 12,978.38, 17,910.30 and 7,389.74

Step by Step Solution

1. Step 1: Write the proportion equation
   12,978.38 : 17,910.30 = 7,389.74 : x
2. Step 2: Convert to fraction form
   12,978.38/17,910.30 = 7,389.74/x
3. Step 3: Cross multiply
   12,978.38x = 17,910.30 × 7,389.74
4. Step 4: Simplify right side
   12,978.38x = 132,352,460.32
5. Step 5: Solve for x
   x = 132,352,460.32/12,978.38
6. Step 6: Final answer
   x = 10,197.92