Finding the Fourth Proportional to 1,557.12, 2,148.72 and 858.40

Step by Step Solution

1. Step 1: Write the proportion equation
   1,557.12 : 2,148.72 = 858.40 : x
2. Step 2: Convert to fraction form
   1,557.12/2,148.72 = 858.40/x
3. Step 3: Cross multiply
   1,557.12x = 2,148.72 × 858.40
4. Step 4: Simplify right side
   1,557.12x = 1,844,461.25
5. Step 5: Solve for x
   x = 1,844,461.25/1,557.12
6. Step 6: Final answer
   x = 1,184.53