Finding the Fourth Proportional to 498.69, 688.10 and 419.85

Step by Step Solution

1. Step 1: Write the proportion equation
   498.69 : 688.10 = 419.85 : x
2. Step 2: Convert to fraction form
   498.69/688.10 = 419.85/x
3. Step 3: Cross multiply
   498.69x = 688.10 × 419.85
4. Step 4: Simplify right side
   498.69x = 288,896.69
5. Step 5: Solve for x
   x = 288,896.69/498.69
6. Step 6: Final answer
   x = 579.31