Finding the Fourth Proportional to 1,137.69, 1,570.05 and 640.29

Step by Step Solution

1. Step 1: Write the proportion equation
   1,137.69 : 1,570.05 = 640.29 : x
2. Step 2: Convert to fraction form
   1,137.69/1,570.05 = 640.29/x
3. Step 3: Cross multiply
   1,137.69x = 1,570.05 × 640.29
4. Step 4: Simplify right side
   1,137.69x = 1,005,287.31
5. Step 5: Solve for x
   x = 1,005,287.31/1,137.69
6. Step 6: Final answer
   x = 883.62