Finding the Fourth Proportional to 1,007.48, 1,390.58 and 614.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,007.48 : 1,390.58 = 614.78 : x
2. Step 2: Convert to fraction form
   1,007.48/1,390.58 = 614.78/x
3. Step 3: Cross multiply
   1,007.48x = 1,390.58 × 614.78
4. Step 4: Simplify right side
   1,007.48x = 854,900.77
5. Step 5: Solve for x
   x = 854,900.77/1,007.48
6. Step 6: Final answer
   x = 848.55