Finding the Fourth Proportional to 1,288.53, 1,778.18 and 699.07

Step by Step Solution

1. Step 1: Write the proportion equation
   1,288.53 : 1,778.18 = 699.07 : x
2. Step 2: Convert to fraction form
   1,288.53/1,778.18 = 699.07/x
3. Step 3: Cross multiply
   1,288.53x = 1,778.18 × 699.07
4. Step 4: Simplify right side
   1,288.53x = 1,243,071.02
5. Step 5: Solve for x
   x = 1,243,071.02/1,288.53
6. Step 6: Final answer
   x = 964.72