Finding the Fourth Proportional to 871.27, 1,201.78 and 498.15

Step by Step Solution

1. Step 1: Write the proportion equation
   871.27 : 1,201.78 = 498.15 : x
2. Step 2: Convert to fraction form
   871.27/1,201.78 = 498.15/x
3. Step 3: Cross multiply
   871.27x = 1,201.78 × 498.15
4. Step 4: Simplify right side
   871.27x = 598,666.71
5. Step 5: Solve for x
   x = 598,666.71/871.27
6. Step 6: Final answer
   x = 687.12