Finding the Fourth Proportional to 1,002.78, 1,510.85 and 905.39

Step by Step Solution

1. Step 1: Write the proportion equation
   1,002.78 : 1,510.85 = 905.39 : x
2. Step 2: Convert to fraction form
   1,002.78/1,510.85 = 905.39/x
3. Step 3: Cross multiply
   1,002.78x = 1,510.85 × 905.39
4. Step 4: Simplify right side
   1,002.78x = 1,367,900.93
5. Step 5: Solve for x
   x = 1,367,900.93/1,002.78
6. Step 6: Final answer
   x = 1,364.12