Finding the Third Proportional to 138,928 and 215,256

Step by Step Solution

1. Step 1: Write the proportion equation
   138,928 : 215,256 = 215,256 : x
2. Step 2: Convert to fraction form
   138,928/215,256 = 215,256/x
3. Step 3: Cross multiply
   138,928x = 215,256 × 215,256
4. Step 4: Simplify right side
   138,928x = 46,335,145,536
5. Step 5: Solve for x
   x = 46,335,145,536/138,928
6. Step 6: Final answer
   x = 333,519.13