Finding the Fourth Proportional to 1,057.77, 1,459.59 and 638.07

Step by Step Solution

1. Step 1: Write the proportion equation
   1,057.77 : 1,459.59 = 638.07 : x
2. Step 2: Convert to fraction form
   1,057.77/1,459.59 = 638.07/x
3. Step 3: Cross multiply
   1,057.77x = 1,459.59 × 638.07
4. Step 4: Simplify right side
   1,057.77x = 931,320.59
5. Step 5: Solve for x
   x = 931,320.59/1,057.77
6. Step 6: Final answer
   x = 880.46