Finding the Fourth Proportional to 21,234, 31,626.72 and 20,123.76

Step by Step Solution

1. Step 1: Write the proportion equation
   21,234 : 31,626.72 = 20,123.76 : x
2. Step 2: Convert to fraction form
   21,234/31,626.72 = 20,123.76/x
3. Step 3: Cross multiply
   21,234x = 31,626.72 × 20,123.76
4. Step 4: Simplify right side
   21,234x = 636,448,522.87
5. Step 5: Solve for x
   x = 636,448,522.87/21,234
6. Step 6: Final answer
   x = 29,973.09