Finding the Fourth Proportional to 498.00, 687.42 and 288.30

Step by Step Solution

1. Step 1: Write the proportion equation
   498.00 : 687.42 = 288.30 : x
2. Step 2: Convert to fraction form
   498.00/687.42 = 288.30/x
3. Step 3: Cross multiply
   498.00x = 687.42 × 288.30
4. Step 4: Simplify right side
   498.00x = 198,182.15
5. Step 5: Solve for x
   x = 198,182.15/498.00
6. Step 6: Final answer
   x = 397.96