Finding the Third Proportional to 639.75 and 1,500.56

Step by Step Solution

1. Step 1: Write the proportion equation
   639.75 : 1,500.56 = 1,500.56 : x
2. Step 2: Convert to fraction form
   639.75/1,500.56 = 1,500.56/x
3. Step 3: Cross multiply
   639.75x = 1,500.56 × 1,500.56
4. Step 4: Simplify right side
   639.75x = 2,251,687.82
5. Step 5: Solve for x
   x = 2,251,687.82/639.75
6. Step 6: Final answer
   x = 3,519.64