Finding the Fourth Proportional to 1,288.79, 1,778.52 and 699.32

Step by Step Solution

1. Step 1: Write the proportion equation
   1,288.79 : 1,778.52 = 699.32 : x
2. Step 2: Convert to fraction form
   1,288.79/1,778.52 = 699.32/x
3. Step 3: Cross multiply
   1,288.79x = 1,778.52 × 699.32
4. Step 4: Simplify right side
   1,288.79x = 1,243,745.71
5. Step 5: Solve for x
   x = 1,243,745.71/1,288.79
6. Step 6: Final answer
   x = 965.05