Finding the Fourth Proportional to 21,222.06, 31,789.34 and 12,430.32

Step by Step Solution

1. Step 1: Write the proportion equation
   21,222.06 : 31,789.34 = 12,430.32 : x
2. Step 2: Convert to fraction form
   21,222.06/31,789.34 = 12,430.32/x
3. Step 3: Cross multiply
   21,222.06x = 31,789.34 × 12,430.32
4. Step 4: Simplify right side
   21,222.06x = 395,151,668.79
5. Step 5: Solve for x
   x = 395,151,668.79/21,222.06
6. Step 6: Final answer
   x = 18,619.85