Finding the Third Proportional to 472.50 and 639.56

Step by Step Solution

1. Step 1: Write the proportion equation
   472.50 : 639.56 = 639.56 : x
2. Step 2: Convert to fraction form
   472.50/639.56 = 639.56/x
3. Step 3: Cross multiply
   472.50x = 639.56 × 639.56
4. Step 4: Simplify right side
   472.50x = 409,040.19
5. Step 5: Solve for x
   x = 409,040.19/472.50
6. Step 6: Final answer
   x = 865.69