Finding the Third Proportional to 128,865,831,111 and 261,406,111,725

Step by Step Solution

1. Step 1: Write the proportion equation
   128,865,831,111 : 261,406,111,725 = 261,406,111,725 : x
2. Step 2: Convert to fraction form
   128,865,831,111/261,406,111,725 = 261,406,111,725/x
3. Step 3: Cross multiply
   128,865,831,111x = 261,406,111,725 × 261,406,111,725
4. Step 4: Simplify right side
   128,865,831,111x = 68,333,155,247,183,181,643,776
5. Step 5: Solve for x
   x = 68,333,155,247,183,181,643,776/128,865,831,111
6. Step 6: Final answer
   x = 530,265,894,830.75