Finding the Fourth Proportional to 1,017.78, 1,517.91 and 919.35

Step by Step Solution

1. Step 1: Write the proportion equation
   1,017.78 : 1,517.91 = 919.35 : x
2. Step 2: Convert to fraction form
   1,017.78/1,517.91 = 919.35/x
3. Step 3: Cross multiply
   1,017.78x = 1,517.91 × 919.35
4. Step 4: Simplify right side
   1,017.78x = 1,395,490.56
5. Step 5: Solve for x
   x = 1,395,490.56/1,017.78
6. Step 6: Final answer
   x = 1,371.11