Finding the Fourth Proportional to 1,141.86, 1,575.63 and 644.47

Step by Step Solution

1. Step 1: Write the proportion equation
   1,141.86 : 1,575.63 = 644.47 : x
2. Step 2: Convert to fraction form
   1,141.86/1,575.63 = 644.47/x
3. Step 3: Cross multiply
   1,141.86x = 1,575.63 × 644.47
4. Step 4: Simplify right side
   1,141.86x = 1,015,446.27
5. Step 5: Solve for x
   x = 1,015,446.27/1,141.86
6. Step 6: Final answer
   x = 889.29