Finding the Fourth Proportional to 498.42, 688.47 and 387.72

Step by Step Solution

1. Step 1: Write the proportion equation
   498.42 : 688.47 = 387.72 : x
2. Step 2: Convert to fraction form
   498.42/688.47 = 387.72/x
3. Step 3: Cross multiply
   498.42x = 688.47 × 387.72
4. Step 4: Simplify right side
   498.42x = 266,933.59
5. Step 5: Solve for x
   x = 266,933.59/498.42
6. Step 6: Final answer
   x = 535.56