Finding the Fourth Proportional to 1,007.67, 1,390.33 and 771.83

Step by Step Solution

1. Step 1: Write the proportion equation
   1,007.67 : 1,390.33 = 771.83 : x
2. Step 2: Convert to fraction form
   1,007.67/1,390.33 = 771.83/x
3. Step 3: Cross multiply
   1,007.67x = 1,390.33 × 771.83
4. Step 4: Simplify right side
   1,007.67x = 1,073,098.40
5. Step 5: Solve for x
   x = 1,073,098.40/1,007.67
6. Step 6: Final answer
   x = 1,064.93