Finding the Fourth Proportional to 1,289.82, 1,779.98 and 765.86

Step by Step Solution

1. Step 1: Write the proportion equation
   1,289.82 : 1,779.98 = 765.86 : x
2. Step 2: Convert to fraction form
   1,289.82/1,779.98 = 765.86/x
3. Step 3: Cross multiply
   1,289.82x = 1,779.98 × 765.86
4. Step 4: Simplify right side
   1,289.82x = 1,363,215.48
5. Step 5: Solve for x
   x = 1,363,215.48/1,289.82
6. Step 6: Final answer
   x = 1,056.90