Finding the Third Proportional to 258,136 and 387,308

Step by Step Solution

1. Step 1: Write the proportion equation
   258,136 : 387,308 = 387,308 : x
2. Step 2: Convert to fraction form
   258,136/387,308 = 387,308/x
3. Step 3: Cross multiply
   258,136x = 387,308 × 387,308
4. Step 4: Simplify right side
   258,136x = 150,007,486,864
5. Step 5: Solve for x
   x = 150,007,486,864/258,136
6. Step 6: Final answer
   x = 581,118.04