Finding the Fourth Proportional to 1,141.39, 1,575.15 and 644.05

Step by Step Solution

1. Step 1: Write the proportion equation
   1,141.39 : 1,575.15 = 644.05 : x
2. Step 2: Convert to fraction form
   1,141.39/1,575.15 = 644.05/x
3. Step 3: Cross multiply
   1,141.39x = 1,575.15 × 644.05
4. Step 4: Simplify right side
   1,141.39x = 1,014,474.91
5. Step 5: Solve for x
   x = 1,014,474.91/1,141.39
6. Step 6: Final answer
   x = 888.81