Finding the Fourth Proportional to 12,431.60, 17,156.52 and 7,128.08

Step by Step Solution

1. Step 1: Write the proportion equation
   12,431.60 : 17,156.52 = 7,128.08 : x
2. Step 2: Convert to fraction form
   12,431.60/17,156.52 = 7,128.08/x
3. Step 3: Cross multiply
   12,431.60x = 17,156.52 × 7,128.08
4. Step 4: Simplify right side
   12,431.60x = 122,293,047.08
5. Step 5: Solve for x
   x = 122,293,047.08/12,431.60
6. Step 6: Final answer
   x = 9,837.27