Finding the Fourth Proportional to 498.78, 687.78 and 333.12

Step by Step Solution

1. Step 1: Write the proportion equation
   498.78 : 687.78 = 333.12 : x
2. Step 2: Convert to fraction form
   498.78/687.78 = 333.12/x
3. Step 3: Cross multiply
   498.78x = 687.78 × 333.12
4. Step 4: Simplify right side
   498.78x = 229,113.27
5. Step 5: Solve for x
   x = 229,113.27/498.78
6. Step 6: Final answer
   x = 459.35