Finding the Fourth Proportional to 1,289.55, 1,779.28 and 729.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,289.55 : 1,779.28 = 729.89 : x
2. Step 2: Convert to fraction form
   1,289.55/1,779.28 = 729.89/x
3. Step 3: Cross multiply
   1,289.55x = 1,779.28 × 729.89
4. Step 4: Simplify right side
   1,289.55x = 1,298,686.69
5. Step 5: Solve for x
   x = 1,298,686.69/1,289.55
6. Step 6: Final answer
   x = 1,007.09