Finding the Fourth Proportional to 1,164.38, 1,606.72 and 640.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,164.38 : 1,606.72 = 640.31 : x
2. Step 2: Convert to fraction form
   1,164.38/1,606.72 = 640.31/x
3. Step 3: Cross multiply
   1,164.38x = 1,606.72 × 640.31
4. Step 4: Simplify right side
   1,164.38x = 1,028,795.68
5. Step 5: Solve for x
   x = 1,028,795.68/1,164.38
6. Step 6: Final answer
   x = 883.56