Finding the Third Proportional to 142,970 and 309,478

Step by Step Solution

1. Step 1: Write the proportion equation
   142,970 : 309,478 = 309,478 : x
2. Step 2: Convert to fraction form
   142,970/309,478 = 309,478/x
3. Step 3: Cross multiply
   142,970x = 309,478 × 309,478
4. Step 4: Simplify right side
   142,970x = 95,776,632,484
5. Step 5: Solve for x
   x = 95,776,632,484/142,970
6. Step 6: Final answer
   x = 669,907.20