Finding the Fourth Proportional to 1,085.97, 1,498.66 and 638.16

Step by Step Solution

1. Step 1: Write the proportion equation
   1,085.97 : 1,498.66 = 638.16 : x
2. Step 2: Convert to fraction form
   1,085.97/1,498.66 = 638.16/x
3. Step 3: Cross multiply
   1,085.97x = 1,498.66 × 638.16
4. Step 4: Simplify right side
   1,085.97x = 956,384.87
5. Step 5: Solve for x
   x = 956,384.87/1,085.97
6. Step 6: Final answer
   x = 880.67