Finding the Third Proportional to 450.56 and 688.78

Step by Step Solution

1. Step 1: Write the proportion equation
   450.56 : 688.78 = 688.78 : x
2. Step 2: Convert to fraction form
   450.56/688.78 = 688.78/x
3. Step 3: Cross multiply
   450.56x = 688.78 × 688.78
4. Step 4: Simplify right side
   450.56x = 474,419.61
5. Step 5: Solve for x
   x = 474,419.61/450.56
6. Step 6: Final answer
   x = 1,052.95