Finding the Fourth Proportional to 1,057.78, 1,459.74 and 615.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,057.78 : 1,459.74 = 615.57 : x
2. Step 2: Convert to fraction form
   1,057.78/1,459.74 = 615.57/x
3. Step 3: Cross multiply
   1,057.78x = 1,459.74 × 615.57
4. Step 4: Simplify right side
   1,057.78x = 898,572.15
5. Step 5: Solve for x
   x = 898,572.15/1,057.78
6. Step 6: Final answer
   x = 849.49