Finding the Fourth Proportional to 1,442.86, 1,991.58 and 904.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,442.86 : 1,991.58 = 904.78 : x
2. Step 2: Convert to fraction form
   1,442.86/1,991.58 = 904.78/x
3. Step 3: Cross multiply
   1,442.86x = 1,991.58 × 904.78
4. Step 4: Simplify right side
   1,442.86x = 1,801,941.75
5. Step 5: Solve for x
   x = 1,801,941.75/1,442.86
6. Step 6: Final answer
   x = 1,248.87