Finding the Fourth Proportional to 21,200.88, 31,801.31 and 12,431.01

Step by Step Solution

1. Step 1: Write the proportion equation
   21,200.88 : 31,801.31 = 12,431.01 : x
2. Step 2: Convert to fraction form
   21,200.88/31,801.31 = 12,431.01/x
3. Step 3: Cross multiply
   21,200.88x = 31,801.31 × 12,431.01
4. Step 4: Simplify right side
   21,200.88x = 395,322,402.62
5. Step 5: Solve for x
   x = 395,322,402.62/21,200.88
6. Step 6: Final answer
   x = 18,646.51