Finding the Third Proportional to 63,140 and 128,456

Step by Step Solution

1. Step 1: Write the proportion equation
   63,140 : 128,456 = 128,456 : x
2. Step 2: Convert to fraction form
   63,140/128,456 = 128,456/x
3. Step 3: Cross multiply
   63,140x = 128,456 × 128,456
4. Step 4: Simplify right side
   63,140x = 16,500,943,936
5. Step 5: Solve for x
   x = 16,500,943,936/63,140
6. Step 6: Final answer
   x = 261,338.99