Finding the Fourth Proportional to 1,141.67, 1,575.50 and 644.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,141.67 : 1,575.50 = 644.31 : x
2. Step 2: Convert to fraction form
   1,141.67/1,575.50 = 644.31/x
3. Step 3: Cross multiply
   1,141.67x = 1,575.50 × 644.31
4. Step 4: Simplify right side
   1,141.67x = 1,015,112.02
5. Step 5: Solve for x
   x = 1,015,112.02/1,141.67
6. Step 6: Final answer
   x = 889.15