Finding the Third Proportional to 144,390 and 215,388

Step by Step Solution

1. Step 1: Write the proportion equation
   144,390 : 215,388 = 215,388 : x
2. Step 2: Convert to fraction form
   144,390/215,388 = 215,388/x
3. Step 3: Cross multiply
   144,390x = 215,388 × 215,388
4. Step 4: Simplify right side
   144,390x = 46,391,990,544
5. Step 5: Solve for x
   x = 46,391,990,544/144,390
6. Step 6: Final answer
   x = 321,296.42