Finding the Fourth Proportional to 1,085.54, 1,498.16 and 643.48

Step by Step Solution

1. Step 1: Write the proportion equation
   1,085.54 : 1,498.16 = 643.48 : x
2. Step 2: Convert to fraction form
   1,085.54/1,498.16 = 643.48/x
3. Step 3: Cross multiply
   1,085.54x = 1,498.16 × 643.48
4. Step 4: Simplify right side
   1,085.54x = 964,037.07
5. Step 5: Solve for x
   x = 964,037.07/1,085.54
6. Step 6: Final answer
   x = 888.07