Finding the Fourth Proportional to 1,086.12, 1,499.01 and 644.13

Step by Step Solution

1. Step 1: Write the proportion equation
   1,086.12 : 1,499.01 = 644.13 : x
2. Step 2: Convert to fraction form
   1,086.12/1,499.01 = 644.13/x
3. Step 3: Cross multiply
   1,086.12x = 1,499.01 × 644.13
4. Step 4: Simplify right side
   1,086.12x = 965,557.31
5. Step 5: Solve for x
   x = 965,557.31/1,086.12
6. Step 6: Final answer
   x = 889.00