Finding the Fourth Proportional to 1,056.39, 1,582.83 and 644.28

Step by Step Solution

1. Step 1: Write the proportion equation
   1,056.39 : 1,582.83 = 644.28 : x
2. Step 2: Convert to fraction form
   1,056.39/1,582.83 = 644.28/x
3. Step 3: Cross multiply
   1,056.39x = 1,582.83 × 644.28
4. Step 4: Simplify right side
   1,056.39x = 1,019,785.71
5. Step 5: Solve for x
   x = 1,019,785.71/1,056.39
6. Step 6: Final answer
   x = 965.35