Finding the Fourth Proportional to 1,377.98, 1,904.34 and 1,128.90

Step by Step Solution

1. Step 1: Write the proportion equation
   1,377.98 : 1,904.34 = 1,128.90 : x
2. Step 2: Convert to fraction form
   1,377.98/1,904.34 = 1,128.90/x
3. Step 3: Cross multiply
   1,377.98x = 1,904.34 × 1,128.90
4. Step 4: Simplify right side
   1,377.98x = 2,149,809.43
5. Step 5: Solve for x
   x = 2,149,809.43/1,377.98
6. Step 6: Final answer
   x = 1,560.12