Finding the Fourth Proportional to 21,443.76, 32,140.72 and 12,686.04

Step by Step Solution

1. Step 1: Write the proportion equation
   21,443.76 : 32,140.72 = 12,686.04 : x
2. Step 2: Convert to fraction form
   21,443.76/32,140.72 = 12,686.04/x
3. Step 3: Cross multiply
   21,443.76x = 32,140.72 × 12,686.04
4. Step 4: Simplify right side
   21,443.76x = 407,738,459.55
5. Step 5: Solve for x
   x = 407,738,459.55/21,443.76
6. Step 6: Final answer
   x = 19,014.32