Finding the Fourth Proportional to 12,886.16, 17,787.20 and 7,853.64

Step by Step Solution

1. Step 1: Write the proportion equation
   12,886.16 : 17,787.20 = 7,853.64 : x
2. Step 2: Convert to fraction form
   12,886.16/17,787.20 = 7,853.64/x
3. Step 3: Cross multiply
   12,886.16x = 17,787.20 × 7,853.64
4. Step 4: Simplify right side
   12,886.16x = 139,694,265.41
5. Step 5: Solve for x
   x = 139,694,265.41/12,886.16
6. Step 6: Final answer
   x = 10,840.64