Finding the Fourth Proportional to 1,055.10, 1,581.73 and 405.38

Step by Step Solution

1. Step 1: Write the proportion equation
   1,055.10 : 1,581.73 = 405.38 : x
2. Step 2: Convert to fraction form
   1,055.10/1,581.73 = 405.38/x
3. Step 3: Cross multiply
   1,055.10x = 1,581.73 × 405.38
4. Step 4: Simplify right side
   1,055.10x = 641,194.31
5. Step 5: Solve for x
   x = 641,194.31/1,055.10
6. Step 6: Final answer
   x = 607.71