Finding the Fourth Proportional to 1,392.49, 1,920.05 and 1,042.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,392.49 : 1,920.05 = 1,042.57 : x
2. Step 2: Convert to fraction form
   1,392.49/1,920.05 = 1,042.57/x
3. Step 3: Cross multiply
   1,392.49x = 1,920.05 × 1,042.57
4. Step 4: Simplify right side
   1,392.49x = 2,001,776.93
5. Step 5: Solve for x
   x = 2,001,776.93/1,392.49
6. Step 6: Final answer
   x = 1,437.56