Finding the Fourth Proportional to 12,928.28, 17,840.79 and 7,185.60

Step by Step Solution

1. Step 1: Write the proportion equation
   12,928.28 : 17,840.79 = 7,185.60 : x
2. Step 2: Convert to fraction form
   12,928.28/17,840.79 = 7,185.60/x
3. Step 3: Cross multiply
   12,928.28x = 17,840.79 × 7,185.60
4. Step 4: Simplify right side
   12,928.28x = 128,196,780.62
5. Step 5: Solve for x
   x = 128,196,780.62/12,928.28
6. Step 6: Final answer
   x = 9,916.00