Finding the Fourth Proportional to 1,399.41, 1,931.04 and 1,005.75

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.41 : 1,931.04 = 1,005.75 : x
2. Step 2: Convert to fraction form
   1,399.41/1,931.04 = 1,005.75/x
3. Step 3: Cross multiply
   1,399.41x = 1,931.04 × 1,005.75
4. Step 4: Simplify right side
   1,399.41x = 1,942,143.48
5. Step 5: Solve for x
   x = 1,942,143.48/1,399.41
6. Step 6: Final answer
   x = 1,387.83