Finding the Fourth Proportional to 1,055.18, 1,581.96 and 644.42

Step by Step Solution

1. Step 1: Write the proportion equation
   1,055.18 : 1,581.96 = 644.42 : x
2. Step 2: Convert to fraction form
   1,055.18/1,581.96 = 644.42/x
3. Step 3: Cross multiply
   1,055.18x = 1,581.96 × 644.42
4. Step 4: Simplify right side
   1,055.18x = 1,019,446.66
5. Step 5: Solve for x
   x = 1,019,446.66/1,055.18
6. Step 6: Final answer
   x = 966.14