Finding the Fourth Proportional to 1,288.92, 1,778.72 and 699.47

Step by Step Solution

1. Step 1: Write the proportion equation
   1,288.92 : 1,778.72 = 699.47 : x
2. Step 2: Convert to fraction form
   1,288.92/1,778.72 = 699.47/x
3. Step 3: Cross multiply
   1,288.92x = 1,778.72 × 699.47
4. Step 4: Simplify right side
   1,288.92x = 1,244,148.89
5. Step 5: Solve for x
   x = 1,244,148.89/1,288.92
6. Step 6: Final answer
   x = 965.26