Finding the Fourth Proportional to 1,141.76, 1,575.45 and 644.33

Step by Step Solution

1. Step 1: Write the proportion equation
   1,141.76 : 1,575.45 = 644.33 : x
2. Step 2: Convert to fraction form
   1,141.76/1,575.45 = 644.33/x
3. Step 3: Cross multiply
   1,141.76x = 1,575.45 × 644.33
4. Step 4: Simplify right side
   1,141.76x = 1,015,101.82
5. Step 5: Solve for x
   x = 1,015,101.82/1,141.76
6. Step 6: Final answer
   x = 889.07