Finding the Fourth Proportional to 12,928.28, 17,842.68 and 7,891.43

Step by Step Solution

1. Step 1: Write the proportion equation
   12,928.28 : 17,842.68 = 7,891.43 : x
2. Step 2: Convert to fraction form
   12,928.28/17,842.68 = 7,891.43/x
3. Step 3: Cross multiply
   12,928.28x = 17,842.68 × 7,891.43
4. Step 4: Simplify right side
   12,928.28x = 140,804,171.02
5. Step 5: Solve for x
   x = 140,804,171.02/12,928.28
6. Step 6: Final answer
   x = 10,891.17