Finding the Third Proportional to 498.75 and 642.75

Step by Step Solution

1. Step 1: Write the proportion equation
   498.75 : 642.75 = 642.75 : x
2. Step 2: Convert to fraction form
   498.75/642.75 = 642.75/x
3. Step 3: Cross multiply
   498.75x = 642.75 × 642.75
4. Step 4: Simplify right side
   498.75x = 413,127.56
5. Step 5: Solve for x
   x = 413,127.56/498.75
6. Step 6: Final answer
   x = 828.33