Finding the Third Proportional to 123,500 and 256,690

Step by Step Solution

1. Step 1: Write the proportion equation
   123,500 : 256,690 = 256,690 : x
2. Step 2: Convert to fraction form
   123,500/256,690 = 256,690/x
3. Step 3: Cross multiply
   123,500x = 256,690 × 256,690
4. Step 4: Simplify right side
   123,500x = 65,889,756,100
5. Step 5: Solve for x
   x = 65,889,756,100/123,500
6. Step 6: Final answer
   x = 533,520.29