Finding the Fourth Proportional to 1,168.37, 1,612.31 and 644.40

Step by Step Solution

1. Step 1: Write the proportion equation
   1,168.37 : 1,612.31 = 644.40 : x
2. Step 2: Convert to fraction form
   1,168.37/1,612.31 = 644.40/x
3. Step 3: Cross multiply
   1,168.37x = 1,612.31 × 644.40
4. Step 4: Simplify right side
   1,168.37x = 1,038,972.56
5. Step 5: Solve for x
   x = 1,038,972.56/1,168.37
6. Step 6: Final answer
   x = 889.25