Finding the Fourth Proportional to 1,086.08, 1,498.03 and 643.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,086.08 : 1,498.03 = 643.61 : x
2. Step 2: Convert to fraction form
   1,086.08/1,498.03 = 643.61/x
3. Step 3: Cross multiply
   1,086.08x = 1,498.03 × 643.61
4. Step 4: Simplify right side
   1,086.08x = 964,149.22
5. Step 5: Solve for x
   x = 964,149.22/1,086.08
6. Step 6: Final answer
   x = 887.74