Finding the Fourth Proportional to 1,378.36, 1,902.35 and 905.42

Step by Step Solution

1. Step 1: Write the proportion equation
   1,378.36 : 1,902.35 = 905.42 : x
2. Step 2: Convert to fraction form
   1,378.36/1,902.35 = 905.42/x
3. Step 3: Cross multiply
   1,378.36x = 1,902.35 × 905.42
4. Step 4: Simplify right side
   1,378.36x = 1,722,416.23
5. Step 5: Solve for x
   x = 1,722,416.23/1,378.36
6. Step 6: Final answer
   x = 1,249.62