Finding the Fourth Proportional to 1,086.37, 1,499.19 and 644.35

Step by Step Solution

1. Step 1: Write the proportion equation
   1,086.37 : 1,499.19 = 644.35 : x
2. Step 2: Convert to fraction form
   1,086.37/1,499.19 = 644.35/x
3. Step 3: Cross multiply
   1,086.37x = 1,499.19 × 644.35
4. Step 4: Simplify right side
   1,086.37x = 966,006.82
5. Step 5: Solve for x
   x = 966,006.82/1,086.37
6. Step 6: Final answer
   x = 889.21