Finding the Third Proportional to 31,878 and 66,380

Step by Step Solution

1. Step 1: Write the proportion equation
   31,878 : 66,380 = 66,380 : x
2. Step 2: Convert to fraction form
   31,878/66,380 = 66,380/x
3. Step 3: Cross multiply
   31,878x = 66,380 × 66,380
4. Step 4: Simplify right side
   31,878x = 4,406,304,400
5. Step 5: Solve for x
   x = 4,406,304,400/31,878
6. Step 6: Final answer
   x = 138,223.99