Finding the Fourth Proportional to 12,888.62, 17,785.42 and 7,222.40

Step by Step Solution

1. Step 1: Write the proportion equation
   12,888.62 : 17,785.42 = 7,222.40 : x
2. Step 2: Convert to fraction form
   12,888.62/17,785.42 = 7,222.40/x
3. Step 3: Cross multiply
   12,888.62x = 17,785.42 × 7,222.40
4. Step 4: Simplify right side
   12,888.62x = 128,453,443.82
5. Step 5: Solve for x
   x = 128,453,443.82/12,888.62
6. Step 6: Final answer
   x = 9,966.42