Finding the Third Proportional to 420,061.50 and 638,856

Step by Step Solution

1. Step 1: Write the proportion equation
   420,061.50 : 638,856 = 638,856 : x
2. Step 2: Convert to fraction form
   420,061.50/638,856 = 638,856/x
3. Step 3: Cross multiply
   420,061.50x = 638,856 × 638,856
4. Step 4: Simplify right side
   420,061.50x = 408,136,988,736
5. Step 5: Solve for x
   x = 408,136,988,736/420,061.50
6. Step 6: Final answer
   x = 971,612.46