Finding the Fourth Proportional to 1,086.67, 1,499.01 and 644.25

Step by Step Solution

1. Step 1: Write the proportion equation
   1,086.67 : 1,499.01 = 644.25 : x
2. Step 2: Convert to fraction form
   1,086.67/1,499.01 = 644.25/x
3. Step 3: Cross multiply
   1,086.67x = 1,499.01 × 644.25
4. Step 4: Simplify right side
   1,086.67x = 965,740.40
5. Step 5: Solve for x
   x = 965,740.40/1,086.67
6. Step 6: Final answer
   x = 888.72