Finding the Fourth Proportional to 498.25, 687.61 and 323.90

Step by Step Solution

1. Step 1: Write the proportion equation
   498.25 : 687.61 = 323.90 : x
2. Step 2: Convert to fraction form
   498.25/687.61 = 323.90/x
3. Step 3: Cross multiply
   498.25x = 687.61 × 323.90
4. Step 4: Simplify right side
   498.25x = 222,716.88
5. Step 5: Solve for x
   x = 222,716.88/498.25
6. Step 6: Final answer
   x = 447.00