Finding the Fourth Proportional to 1,603.94, 2,213.60 and 905.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,603.94 : 2,213.60 = 905.31 : x
2. Step 2: Convert to fraction form
   1,603.94/2,213.60 = 905.31/x
3. Step 3: Cross multiply
   1,603.94x = 2,213.60 × 905.31
4. Step 4: Simplify right side
   1,603.94x = 2,003,989.69
5. Step 5: Solve for x
   x = 2,003,989.69/1,603.94
6. Step 6: Final answer
   x = 1,249.42