Finding the Fourth Proportional to 1,137.71, 1,570.05 and 640.34

Step by Step Solution

1. Step 1: Write the proportion equation
   1,137.71 : 1,570.05 = 640.34 : x
2. Step 2: Convert to fraction form
   1,137.71/1,570.05 = 640.34/x
3. Step 3: Cross multiply
   1,137.71x = 1,570.05 × 640.34
4. Step 4: Simplify right side
   1,137.71x = 1,005,365.82
5. Step 5: Solve for x
   x = 1,005,365.82/1,137.71
6. Step 6: Final answer
   x = 883.67