Finding the Fourth Proportional to 1,086.80, 1,499.82 and 644.96

Step by Step Solution

1. Step 1: Write the proportion equation
   1,086.80 : 1,499.82 = 644.96 : x
2. Step 2: Convert to fraction form
   1,086.80/1,499.82 = 644.96/x
3. Step 3: Cross multiply
   1,086.80x = 1,499.82 × 644.96
4. Step 4: Simplify right side
   1,086.80x = 967,323.91
5. Step 5: Solve for x
   x = 967,323.91/1,086.80
6. Step 6: Final answer
   x = 890.07