Finding the Fourth Proportional to 12,938.40, 17,859.60 and 7,837.92

Step by Step Solution

1. Step 1: Write the proportion equation
   12,938.40 : 17,859.60 = 7,837.92 : x
2. Step 2: Convert to fraction form
   12,938.40/17,859.60 = 7,837.92/x
3. Step 3: Cross multiply
   12,938.40x = 17,859.60 × 7,837.92
4. Step 4: Simplify right side
   12,938.40x = 139,982,116.03
5. Step 5: Solve for x
   x = 139,982,116.03/12,938.40
6. Step 6: Final answer
   x = 10,819.12