Finding the Fourth Proportional to 1,142.32, 1,576.39 and 644.98

Step by Step Solution

1. Step 1: Write the proportion equation
   1,142.32 : 1,576.39 = 644.98 : x
2. Step 2: Convert to fraction form
   1,142.32/1,576.39 = 644.98/x
3. Step 3: Cross multiply
   1,142.32x = 1,576.39 × 644.98
4. Step 4: Simplify right side
   1,142.32x = 1,016,738.63
5. Step 5: Solve for x
   x = 1,016,738.63/1,142.32
6. Step 6: Final answer
   x = 890.07