Finding the Fourth Proportional to 12,968.57, 17,968.91 and 12,688.31

Step by Step Solution

1. Step 1: Write the proportion equation
   12,968.57 : 17,968.91 = 12,688.31 : x
2. Step 2: Convert to fraction form
   12,968.57/17,968.91 = 12,688.31/x
3. Step 3: Cross multiply
   12,968.57x = 17,968.91 × 12,688.31
4. Step 4: Simplify right side
   12,968.57x = 227,995,081.92
5. Step 5: Solve for x
   x = 227,995,081.92/12,968.57
6. Step 6: Final answer
   x = 17,580.58