Finding the Fourth Proportional to 12,885.12, 17,780.85 and 7,219.17

Step by Step Solution

1. Step 1: Write the proportion equation
   12,885.12 : 17,780.85 = 7,219.17 : x
2. Step 2: Convert to fraction form
   12,885.12/17,780.85 = 7,219.17/x
3. Step 3: Cross multiply
   12,885.12x = 17,780.85 × 7,219.17
4. Step 4: Simplify right side
   12,885.12x = 128,362,978.89
5. Step 5: Solve for x
   x = 128,362,978.89/12,885.12
6. Step 6: Final answer
   x = 9,962.11