Finding the Fourth Proportional to 498.78, 688.31 and 277.72

Step by Step Solution

1. Step 1: Write the proportion equation
   498.78 : 688.31 = 277.72 : x
2. Step 2: Convert to fraction form
   498.78/688.31 = 277.72/x
3. Step 3: Cross multiply
   498.78x = 688.31 × 277.72
4. Step 4: Simplify right side
   498.78x = 191,157.45
5. Step 5: Solve for x
   x = 191,157.45/498.78
6. Step 6: Final answer
   x = 383.25