Finding the Third Proportional to 516.56 and 628.78

Step by Step Solution

1. Step 1: Write the proportion equation
   516.56 : 628.78 = 628.78 : x
2. Step 2: Convert to fraction form
   516.56/628.78 = 628.78/x
3. Step 3: Cross multiply
   516.56x = 628.78 × 628.78
4. Step 4: Simplify right side
   516.56x = 395,365.86
5. Step 5: Solve for x
   x = 395,365.86/516.56
6. Step 6: Final answer
   x = 765.38