Finding the Third Proportional to 21,378 and 31,839

Step by Step Solution

1. Step 1: Write the proportion equation
   21,378 : 31,839 = 31,839 : x
2. Step 2: Convert to fraction form
   21,378/31,839 = 31,839/x
3. Step 3: Cross multiply
   21,378x = 31,839 × 31,839
4. Step 4: Simplify right side
   21,378x = 1,013,721,921
5. Step 5: Solve for x
   x = 1,013,721,921/21,378
6. Step 6: Final answer
   x = 47,418.93