Finding the Fourth Proportional to 1,209.31, 1,821.42 and 1,123.76

Step by Step Solution

1. Step 1: Write the proportion equation
   1,209.31 : 1,821.42 = 1,123.76 : x
2. Step 2: Convert to fraction form
   1,209.31/1,821.42 = 1,123.76/x
3. Step 3: Cross multiply
   1,209.31x = 1,821.42 × 1,123.76
4. Step 4: Simplify right side
   1,209.31x = 2,046,833.25
5. Step 5: Solve for x
   x = 2,046,833.25/1,209.31
6. Step 6: Final answer
   x = 1,692.56