Finding the Fourth Proportional to 1,391.99, 1,919.36 and 1,042.07

Step by Step Solution

1. Step 1: Write the proportion equation
   1,391.99 : 1,919.36 = 1,042.07 : x
2. Step 2: Convert to fraction form
   1,391.99/1,919.36 = 1,042.07/x
3. Step 3: Cross multiply
   1,391.99x = 1,919.36 × 1,042.07
4. Step 4: Simplify right side
   1,391.99x = 2,000,100.48
5. Step 5: Solve for x
   x = 2,000,100.48/1,391.99
6. Step 6: Final answer
   x = 1,436.87