Finding the Fourth Proportional to 1,057.90, 1,585.89 and 409.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,057.90 : 1,585.89 = 409.12 : x
2. Step 2: Convert to fraction form
   1,057.90/1,585.89 = 409.12/x
3. Step 3: Cross multiply
   1,057.90x = 1,585.89 × 409.12
4. Step 4: Simplify right side
   1,057.90x = 648,819.32
5. Step 5: Solve for x
   x = 648,819.32/1,057.90
6. Step 6: Final answer
   x = 613.31