Finding the Fourth Proportional to 498.18, 687.38 and 291.18

Step by Step Solution

1. Step 1: Write the proportion equation
   498.18 : 687.38 = 291.18 : x
2. Step 2: Convert to fraction form
   498.18/687.38 = 291.18/x
3. Step 3: Cross multiply
   498.18x = 687.38 × 291.18
4. Step 4: Simplify right side
   498.18x = 200,151.31
5. Step 5: Solve for x
   x = 200,151.31/498.18
6. Step 6: Final answer
   x = 401.77