Finding the Third Proportional to 138,434.50 and 216,879

Step by Step Solution

1. Step 1: Write the proportion equation
   138,434.50 : 216,879 = 216,879 : x
2. Step 2: Convert to fraction form
   138,434.50/216,879 = 216,879/x
3. Step 3: Cross multiply
   138,434.50x = 216,879 × 216,879
4. Step 4: Simplify right side
   138,434.50x = 47,036,500,641
5. Step 5: Solve for x
   x = 47,036,500,641/138,434.50
6. Step 6: Final answer
   x = 339,774.41