Finding the Fourth Proportional to 1,557.82, 2,149.78 and 859.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,557.82 : 2,149.78 = 859.20 : x
2. Step 2: Convert to fraction form
   1,557.82/2,149.78 = 859.20/x
3. Step 3: Cross multiply
   1,557.82x = 2,149.78 × 859.20
4. Step 4: Simplify right side
   1,557.82x = 1,847,090.98
5. Step 5: Solve for x
   x = 1,847,090.98/1,557.82
6. Step 6: Final answer
   x = 1,185.69