Finding the Fourth Proportional to 1,854.20, 2,558.78 and 1,191.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,854.20 : 2,558.78 = 1,191.31 : x
2. Step 2: Convert to fraction form
   1,854.20/2,558.78 = 1,191.31/x
3. Step 3: Cross multiply
   1,854.20x = 2,558.78 × 1,191.31
4. Step 4: Simplify right side
   1,854.20x = 3,048,300.20
5. Step 5: Solve for x
   x = 3,048,300.20/1,854.20
6. Step 6: Final answer
   x = 1,644.00