Finding the Fourth Proportional to 1,056.36, 1,581.86 and 644.24

Step by Step Solution

1. Step 1: Write the proportion equation
   1,056.36 : 1,581.86 = 644.24 : x
2. Step 2: Convert to fraction form
   1,056.36/1,581.86 = 644.24/x
3. Step 3: Cross multiply
   1,056.36x = 1,581.86 × 644.24
4. Step 4: Simplify right side
   1,056.36x = 1,019,097.49
5. Step 5: Solve for x
   x = 1,019,097.49/1,056.36
6. Step 6: Final answer
   x = 964.73