Finding the Fourth Proportional to 12,890.86, 17,788.30 and 7,148.48

Step by Step Solution

1. Step 1: Write the proportion equation
   12,890.86 : 17,788.30 = 7,148.48 : x
2. Step 2: Convert to fraction form
   12,890.86/17,788.30 = 7,148.48/x
3. Step 3: Cross multiply
   12,890.86x = 17,788.30 × 7,148.48
4. Step 4: Simplify right side
   12,890.86x = 127,159,306.78
5. Step 5: Solve for x
   x = 127,159,306.78/12,890.86
6. Step 6: Final answer
   x = 9,864.30