Finding the Fourth Proportional to 12,787.25, 17,644.56 and 7,121.21

Step by Step Solution

1. Step 1: Write the proportion equation
   12,787.25 : 17,644.56 = 7,121.21 : x
2. Step 2: Convert to fraction form
   12,787.25/17,644.56 = 7,121.21/x
3. Step 3: Cross multiply
   12,787.25x = 17,644.56 × 7,121.21
4. Step 4: Simplify right side
   12,787.25x = 125,650,528.89
5. Step 5: Solve for x
   x = 125,650,528.89/12,787.25
6. Step 6: Final answer
   x = 9,826.24