Finding the Fourth Proportional to 12,978.30, 17,912.33 and 12,386.66

Step by Step Solution

1. Step 1: Write the proportion equation
   12,978.30 : 17,912.33 = 12,386.66 : x
2. Step 2: Convert to fraction form
   12,978.30/17,912.33 = 12,386.66/x
3. Step 3: Cross multiply
   12,978.30x = 17,912.33 × 12,386.66
4. Step 4: Simplify right side
   12,978.30x = 221,873,790.02
5. Step 5: Solve for x
   x = 221,873,790.02/12,978.30
6. Step 6: Final answer
   x = 17,095.75