Finding the Fourth Proportional to 1,074.05, 1,608.63 and 640.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,074.05 : 1,608.63 = 640.31 : x
2. Step 2: Convert to fraction form
   1,074.05/1,608.63 = 640.31/x
3. Step 3: Cross multiply
   1,074.05x = 1,608.63 × 640.31
4. Step 4: Simplify right side
   1,074.05x = 1,030,021.88
5. Step 5: Solve for x
   x = 1,030,021.88/1,074.05
6. Step 6: Final answer
   x = 959.01