Finding the Fourth Proportional to 1,380.94, 2,071.31 and 406.96

Step by Step Solution

1. Step 1: Write the proportion equation
   1,380.94 : 2,071.31 = 406.96 : x
2. Step 2: Convert to fraction form
   1,380.94/2,071.31 = 406.96/x
3. Step 3: Cross multiply
   1,380.94x = 2,071.31 × 406.96
4. Step 4: Simplify right side
   1,380.94x = 842,940.32
5. Step 5: Solve for x
   x = 842,940.32/1,380.94
6. Step 6: Final answer
   x = 610.41