Finding the Third Proportional to 142,218 and 213,689

Step by Step Solution

1. Step 1: Write the proportion equation
   142,218 : 213,689 = 213,689 : x
2. Step 2: Convert to fraction form
   142,218/213,689 = 213,689/x
3. Step 3: Cross multiply
   142,218x = 213,689 × 213,689
4. Step 4: Simplify right side
   142,218x = 45,662,988,721
5. Step 5: Solve for x
   x = 45,662,988,721/142,218
6. Step 6: Final answer
   x = 321,077.42