Finding the Fourth Proportional to 1,057.28, 1,459.31 and 615.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,057.28 : 1,459.31 = 615.15 : x
2. Step 2: Convert to fraction form
   1,057.28/1,459.31 = 615.15/x
3. Step 3: Cross multiply
   1,057.28x = 1,459.31 × 615.15
4. Step 4: Simplify right side
   1,057.28x = 897,691.47
5. Step 5: Solve for x
   x = 897,691.47/1,057.28
6. Step 6: Final answer
   x = 849.06