Finding the Fourth Proportional to 1,288.56, 1,777.89 and 1,008.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,288.56 : 1,777.89 = 1,008.30 : x
2. Step 2: Convert to fraction form
   1,288.56/1,777.89 = 1,008.30/x
3. Step 3: Cross multiply
   1,288.56x = 1,777.89 × 1,008.30
4. Step 4: Simplify right side
   1,288.56x = 1,792,646.49
5. Step 5: Solve for x
   x = 1,792,646.49/1,288.56
6. Step 6: Final answer
   x = 1,391.20