Finding the Fourth Proportional to 8,172.72, 12,259.12 and 2,978.60

Step by Step Solution

1. Step 1: Write the proportion equation
   8,172.72 : 12,259.12 = 2,978.60 : x
2. Step 2: Convert to fraction form
   8,172.72/12,259.12 = 2,978.60/x
3. Step 3: Cross multiply
   8,172.72x = 12,259.12 × 2,978.60
4. Step 4: Simplify right side
   8,172.72x = 36,515,014.83
5. Step 5: Solve for x
   x = 36,515,014.83/8,172.72
6. Step 6: Final answer
   x = 4,467.91