Finding the Third Proportional to 21,139.50 and 38,860.50

Step by Step Solution

1. Step 1: Write the proportion equation
   21,139.50 : 38,860.50 = 38,860.50 : x
2. Step 2: Convert to fraction form
   21,139.50/38,860.50 = 38,860.50/x
3. Step 3: Cross multiply
   21,139.50x = 38,860.50 × 38,860.50
4. Step 4: Simplify right side
   21,139.50x = 1,510,138,460.25
5. Step 5: Solve for x
   x = 1,510,138,460.25/21,139.50
6. Step 6: Final answer
   x = 71,436.81