Finding the Fourth Proportional to 1,039.71, 1,560.18 and 423.37

Step by Step Solution

1. Step 1: Write the proportion equation
   1,039.71 : 1,560.18 = 423.37 : x
2. Step 2: Convert to fraction form
   1,039.71/1,560.18 = 423.37/x
3. Step 3: Cross multiply
   1,039.71x = 1,560.18 × 423.37
4. Step 4: Simplify right side
   1,039.71x = 660,525.61
5. Step 5: Solve for x
   x = 660,525.61/1,039.71
6. Step 6: Final answer
   x = 635.30