Finding the Fourth Proportional to 717,648, 990,399.72 and 395,358.72

Step by Step Solution

1. Step 1: Write the proportion equation
   717,648 : 990,399.72 = 395,358.72 : x
2. Step 2: Convert to fraction form
   717,648/990,399.72 = 395,358.72/x
3. Step 3: Cross multiply
   717,648x = 990,399.72 × 395,358.72
4. Step 4: Simplify right side
   717,648x = 391,563,165,587.56
5. Step 5: Solve for x
   x = 391,563,165,587.56/717,648
6. Step 6: Final answer
   x = 545,620.09