Finding the Third Proportional to 142,721 and 310,870

Step by Step Solution

1. Step 1: Write the proportion equation
   142,721 : 310,870 = 310,870 : x
2. Step 2: Convert to fraction form
   142,721/310,870 = 310,870/x
3. Step 3: Cross multiply
   142,721x = 310,870 × 310,870
4. Step 4: Simplify right side
   142,721x = 96,640,156,900
5. Step 5: Solve for x
   x = 96,640,156,900/142,721
6. Step 6: Final answer
   x = 677,126.40