Finding the Fourth Proportional to 1,086.01, 1,498.62 and 643.87

Step by Step Solution

1. Step 1: Write the proportion equation
   1,086.01 : 1,498.62 = 643.87 : x
2. Step 2: Convert to fraction form
   1,086.01/1,498.62 = 643.87/x
3. Step 3: Cross multiply
   1,086.01x = 1,498.62 × 643.87
4. Step 4: Simplify right side
   1,086.01x = 964,916.46
5. Step 5: Solve for x
   x = 964,916.46/1,086.01
6. Step 6: Final answer
   x = 888.50