Finding the Fourth Proportional to 1,057.90, 1,459.91 and 638.27

Step by Step Solution

1. Step 1: Write the proportion equation
   1,057.90 : 1,459.91 = 638.27 : x
2. Step 2: Convert to fraction form
   1,057.90/1,459.91 = 638.27/x
3. Step 3: Cross multiply
   1,057.90x = 1,459.91 × 638.27
4. Step 4: Simplify right side
   1,057.90x = 931,816.76
5. Step 5: Solve for x
   x = 931,816.76/1,057.90
6. Step 6: Final answer
   x = 880.82