Finding the Fourth Proportional to 1,142.19, 1,576.24 and 644.83

Step by Step Solution

1. Step 1: Write the proportion equation
   1,142.19 : 1,576.24 = 644.83 : x
2. Step 2: Convert to fraction form
   1,142.19/1,576.24 = 644.83/x
3. Step 3: Cross multiply
   1,142.19x = 1,576.24 × 644.83
4. Step 4: Simplify right side
   1,142.19x = 1,016,401.29
5. Step 5: Solve for x
   x = 1,016,401.29/1,142.19
6. Step 6: Final answer
   x = 889.87