Finding the Fourth Proportional to 1,039.59, 1,558.89 and 422.79

Step by Step Solution

1. Step 1: Write the proportion equation
   1,039.59 : 1,558.89 = 422.79 : x
2. Step 2: Convert to fraction form
   1,039.59/1,558.89 = 422.79/x
3. Step 3: Cross multiply
   1,039.59x = 1,558.89 × 422.79
4. Step 4: Simplify right side
   1,039.59x = 659,083.10
5. Step 5: Solve for x
   x = 659,083.10/1,039.59
6. Step 6: Final answer
   x = 633.98