Finding the Third Proportional to 489,309 and 689,061

Step by Step Solution

1. Step 1: Write the proportion equation
   489,309 : 689,061 = 689,061 : x
2. Step 2: Convert to fraction form
   489,309/689,061 = 689,061/x
3. Step 3: Cross multiply
   489,309x = 689,061 × 689,061
4. Step 4: Simplify right side
   489,309x = 474,805,061,721
5. Step 5: Solve for x
   x = 474,805,061,721/489,309
6. Step 6: Final answer
   x = 970,358.33