Finding the Third Proportional to 258,709 and 386,467.50

Step by Step Solution

1. Step 1: Write the proportion equation
   258,709 : 386,467.50 = 386,467.50 : x
2. Step 2: Convert to fraction form
   258,709/386,467.50 = 386,467.50/x
3. Step 3: Cross multiply
   258,709x = 386,467.50 × 386,467.50
4. Step 4: Simplify right side
   258,709x = 149,357,128,556.25
5. Step 5: Solve for x
   x = 149,357,128,556.25/258,709
6. Step 6: Final answer
   x = 577,317.10