Finding the Fourth Proportional to 12,978.48, 17,900.72 and 8,946.60

Step by Step Solution

1. Step 1: Write the proportion equation
   12,978.48 : 17,900.72 = 8,946.60 : x
2. Step 2: Convert to fraction form
   12,978.48/17,900.72 = 8,946.60/x
3. Step 3: Cross multiply
   12,978.48x = 17,900.72 × 8,946.60
4. Step 4: Simplify right side
   12,978.48x = 160,150,536.82
5. Step 5: Solve for x
   x = 160,150,536.82/12,978.48
6. Step 6: Final answer
   x = 12,339.70