Finding the Fourth Proportional to 1,086.05, 1,498.94 and 643.93

Step by Step Solution

1. Step 1: Write the proportion equation
   1,086.05 : 1,498.94 = 643.93 : x
2. Step 2: Convert to fraction form
   1,086.05/1,498.94 = 643.93/x
3. Step 3: Cross multiply
   1,086.05x = 1,498.94 × 643.93
4. Step 4: Simplify right side
   1,086.05x = 965,212.43
5. Step 5: Solve for x
   x = 965,212.43/1,086.05
6. Step 6: Final answer
   x = 888.74