Finding the Fourth Proportional to 1,168.71, 1,612.81 and 644.74

Step by Step Solution

1. Step 1: Write the proportion equation
   1,168.71 : 1,612.81 = 644.74 : x
2. Step 2: Convert to fraction form
   1,168.71/1,612.81 = 644.74/x
3. Step 3: Cross multiply
   1,168.71x = 1,612.81 × 644.74
4. Step 4: Simplify right side
   1,168.71x = 1,039,843.12
5. Step 5: Solve for x
   x = 1,039,843.12/1,168.71
6. Step 6: Final answer
   x = 889.74