Finding the Fourth Proportional to 1,057.58, 1,459.49 and 664.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,057.58 : 1,459.49 = 664.61 : x
2. Step 2: Convert to fraction form
   1,057.58/1,459.49 = 664.61/x
3. Step 3: Cross multiply
   1,057.58x = 1,459.49 × 664.61
4. Step 4: Simplify right side
   1,057.58x = 969,981.03
5. Step 5: Solve for x
   x = 969,981.03/1,057.58
6. Step 6: Final answer
   x = 917.17