Finding the Third Proportional to 31,420 and 67,760

Step by Step Solution

1. Step 1: Write the proportion equation
   31,420 : 67,760 = 67,760 : x
2. Step 2: Convert to fraction form
   31,420/67,760 = 67,760/x
3. Step 3: Cross multiply
   31,420x = 67,760 × 67,760
4. Step 4: Simplify right side
   31,420x = 4,591,417,600
5. Step 5: Solve for x
   x = 4,591,417,600/31,420
6. Step 6: Final answer
   x = 146,130.41