Finding the Fourth Proportional to 1,401.44, 1,931.31 and 1,007.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,401.44 : 1,931.31 = 1,007.78 : x
2. Step 2: Convert to fraction form
   1,401.44/1,931.31 = 1,007.78/x
3. Step 3: Cross multiply
   1,401.44x = 1,931.31 × 1,007.78
4. Step 4: Simplify right side
   1,401.44x = 1,946,335.59
5. Step 5: Solve for x
   x = 1,946,335.59/1,401.44
6. Step 6: Final answer
   x = 1,388.81