Finding the Fourth Proportional to 21,555.30, 29,746.56 and 12,123.78

Step by Step Solution

1. Step 1: Write the proportion equation
   21,555.30 : 29,746.56 = 12,123.78 : x
2. Step 2: Convert to fraction form
   21,555.30/29,746.56 = 12,123.78/x
3. Step 3: Cross multiply
   21,555.30x = 29,746.56 × 12,123.78
4. Step 4: Simplify right side
   21,555.30x = 360,640,749.20
5. Step 5: Solve for x
   x = 360,640,749.20/21,555.30
6. Step 6: Final answer
   x = 16,730.95