Finding the Fourth Proportional to 20,387.12, 28,131.72 and 12,002

Step by Step Solution

1. Step 1: Write the proportion equation
   20,387.12 : 28,131.72 = 12,002 : x
2. Step 2: Convert to fraction form
   20,387.12/28,131.72 = 12,002/x
3. Step 3: Cross multiply
   20,387.12x = 28,131.72 × 12,002
4. Step 4: Simplify right side
   20,387.12x = 337,636,903.44
5. Step 5: Solve for x
   x = 337,636,903.44/20,387.12
6. Step 6: Final answer
   x = 16,561.28