Finding the Fourth Proportional to 21,399, 31,941.75 and 18,873.96

Step by Step Solution

1. Step 1: Write the proportion equation
   21,399 : 31,941.75 = 18,873.96 : x
2. Step 2: Convert to fraction form
   21,399/31,941.75 = 18,873.96/x
3. Step 3: Cross multiply
   21,399x = 31,941.75 × 18,873.96
4. Step 4: Simplify right side
   21,399x = 602,867,311.83
5. Step 5: Solve for x
   x = 602,867,311.83/21,399
6. Step 6: Final answer
   x = 28,172.69