Finding the Fourth Proportional to 1,137.81, 1,570.25 and 640.47

Step by Step Solution

1. Step 1: Write the proportion equation
   1,137.81 : 1,570.25 = 640.47 : x
2. Step 2: Convert to fraction form
   1,137.81/1,570.25 = 640.47/x
3. Step 3: Cross multiply
   1,137.81x = 1,570.25 × 640.47
4. Step 4: Simplify right side
   1,137.81x = 1,005,694.82
5. Step 5: Solve for x
   x = 1,005,694.82/1,137.81
6. Step 6: Final answer
   x = 883.89