Finding the Third Proportional to 216,856 and 338,399.50

Step by Step Solution

1. Step 1: Write the proportion equation
   216,856 : 338,399.50 = 338,399.50 : x
2. Step 2: Convert to fraction form
   216,856/338,399.50 = 338,399.50/x
3. Step 3: Cross multiply
   216,856x = 338,399.50 × 338,399.50
4. Step 4: Simplify right side
   216,856x = 114,514,221,600.25
5. Step 5: Solve for x
   x = 114,514,221,600.25/216,856
6. Step 6: Final answer
   x = 528,065.73