Finding the Third Proportional to 128,865,831,115 and 261,406,111,733

Step by Step Solution

1. Step 1: Write the proportion equation
   128,865,831,115 : 261,406,111,733 = 261,406,111,733 : x
2. Step 2: Convert to fraction form
   128,865,831,115/261,406,111,733 = 261,406,111,733/x
3. Step 3: Cross multiply
   128,865,831,115x = 261,406,111,733 × 261,406,111,733
4. Step 4: Simplify right side
   128,865,831,115x = 68,333,155,251,365,682,872,320
5. Step 5: Solve for x
   x = 68,333,155,251,365,682,872,320/128,865,831,115
6. Step 6: Final answer
   x = 530,265,894,846.75