Finding the Fourth Proportional to 1,137.57, 1,569.81 and 640.23

Step by Step Solution

1. Step 1: Write the proportion equation
   1,137.57 : 1,569.81 = 640.23 : x
2. Step 2: Convert to fraction form
   1,137.57/1,569.81 = 640.23/x
3. Step 3: Cross multiply
   1,137.57x = 1,569.81 × 640.23
4. Step 4: Simplify right side
   1,137.57x = 1,005,039.46
5. Step 5: Solve for x
   x = 1,005,039.46/1,137.57
6. Step 6: Final answer
   x = 883.50