Finding the Fourth Proportional to 498.24, 687.55 and 288.42

Step by Step Solution

1. Step 1: Write the proportion equation
   498.24 : 687.55 = 288.42 : x
2. Step 2: Convert to fraction form
   498.24/687.55 = 288.42/x
3. Step 3: Cross multiply
   498.24x = 687.55 × 288.42
4. Step 4: Simplify right side
   498.24x = 198,303.17
5. Step 5: Solve for x
   x = 198,303.17/498.24
6. Step 6: Final answer
   x = 398.01