Finding the Third Proportional to 630.56 and 690.56

Step by Step Solution

1. Step 1: Write the proportion equation
   630.56 : 690.56 = 690.56 : x
2. Step 2: Convert to fraction form
   630.56/690.56 = 690.56/x
3. Step 3: Cross multiply
   630.56x = 690.56 × 690.56
4. Step 4: Simplify right side
   630.56x = 476,876.57
5. Step 5: Solve for x
   x = 476,876.57/630.56
6. Step 6: Final answer
   x = 756.27