Finding the Fourth Proportional to 12,688.86, 17,511.54 and 7,312.16

Step by Step Solution

1. Step 1: Write the proportion equation
   12,688.86 : 17,511.54 = 7,312.16 : x
2. Step 2: Convert to fraction form
   12,688.86/17,511.54 = 7,312.16/x
3. Step 3: Cross multiply
   12,688.86x = 17,511.54 × 7,312.16
4. Step 4: Simplify right side
   12,688.86x = 128,047,182.33
5. Step 5: Solve for x
   x = 128,047,182.33/12,688.86
6. Step 6: Final answer
   x = 10,091.31