Finding the Fourth Proportional to 1,086.36, 1,498.74 and 644.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,086.36 : 1,498.74 = 644.10 : x
2. Step 2: Convert to fraction form
   1,086.36/1,498.74 = 644.10/x
3. Step 3: Cross multiply
   1,086.36x = 1,498.74 × 644.10
4. Step 4: Simplify right side
   1,086.36x = 965,338.43
5. Step 5: Solve for x
   x = 965,338.43/1,086.36
6. Step 6: Final answer
   x = 888.60