Finding the Fourth Proportional to 1,139.52, 1,709.83 and 409.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,139.52 : 1,709.83 = 409.15 : x
2. Step 2: Convert to fraction form
   1,139.52/1,709.83 = 409.15/x
3. Step 3: Cross multiply
   1,139.52x = 1,709.83 × 409.15
4. Step 4: Simplify right side
   1,139.52x = 699,576.94
5. Step 5: Solve for x
   x = 699,576.94/1,139.52
6. Step 6: Final answer
   x = 613.92