Finding the Fourth Proportional to 1,235.91, 1,854.31 and 578.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,235.91 : 1,854.31 = 578.15 : x
2. Step 2: Convert to fraction form
   1,235.91/1,854.31 = 578.15/x
3. Step 3: Cross multiply
   1,235.91x = 1,854.31 × 578.15
4. Step 4: Simplify right side
   1,235.91x = 1,072,069.33
5. Step 5: Solve for x
   x = 1,072,069.33/1,235.91
6. Step 6: Final answer
   x = 867.43