Finding the Third Proportional to 65,870 and 128,428

Step by Step Solution

1. Step 1: Write the proportion equation
   65,870 : 128,428 = 128,428 : x
2. Step 2: Convert to fraction form
   65,870/128,428 = 128,428/x
3. Step 3: Cross multiply
   65,870x = 128,428 × 128,428
4. Step 4: Simplify right side
   65,870x = 16,493,751,184
5. Step 5: Solve for x
   x = 16,493,751,184/65,870
6. Step 6: Final answer
   x = 250,398.53