Finding the Fourth Proportional to 12,885.36, 17,780.72 and 7,142.97

Step by Step Solution

1. Step 1: Write the proportion equation
   12,885.36 : 17,780.72 = 7,142.97 : x
2. Step 2: Convert to fraction form
   12,885.36/17,780.72 = 7,142.97/x
3. Step 3: Cross multiply
   12,885.36x = 17,780.72 × 7,142.97
4. Step 4: Simplify right side
   12,885.36x = 127,007,113.82
5. Step 5: Solve for x
   x = 127,007,113.82/12,885.36
6. Step 6: Final answer
   x = 9,856.70