Finding the Fourth Proportional to 1,143.18, 1,577.54 and 645.82

Step by Step Solution

1. Step 1: Write the proportion equation
   1,143.18 : 1,577.54 = 645.82 : x
2. Step 2: Convert to fraction form
   1,143.18/1,577.54 = 645.82/x
3. Step 3: Cross multiply
   1,143.18x = 1,577.54 × 645.82
4. Step 4: Simplify right side
   1,143.18x = 1,018,806.88
5. Step 5: Solve for x
   x = 1,018,806.88/1,143.18
6. Step 6: Final answer
   x = 891.20