Finding the Fourth Proportional to 21,365.57, 31,967.04 and 12,900.92

Step by Step Solution

1. Step 1: Write the proportion equation
   21,365.57 : 31,967.04 = 12,900.92 : x
2. Step 2: Convert to fraction form
   21,365.57/31,967.04 = 12,900.92/x
3. Step 3: Cross multiply
   21,365.57x = 31,967.04 × 12,900.92
4. Step 4: Simplify right side
   21,365.57x = 412,404,294.03
5. Step 5: Solve for x
   x = 412,404,294.03/21,365.57
6. Step 6: Final answer
   x = 19,302.28