Finding the Fourth Proportional to 1,378.23, 1,902.06 and 1,128.83

Step by Step Solution

1. Step 1: Write the proportion equation
   1,378.23 : 1,902.06 = 1,128.83 : x
2. Step 2: Convert to fraction form
   1,378.23/1,902.06 = 1,128.83/x
3. Step 3: Cross multiply
   1,378.23x = 1,902.06 × 1,128.83
4. Step 4: Simplify right side
   1,378.23x = 2,147,092.88
5. Step 5: Solve for x
   x = 2,147,092.88/1,378.23
6. Step 6: Final answer
   x = 1,557.86