Finding the Third Proportional to 21,290 and 43,640

Step by Step Solution

1. Step 1: Write the proportion equation
   21,290 : 43,640 = 43,640 : x
2. Step 2: Convert to fraction form
   21,290/43,640 = 43,640/x
3. Step 3: Cross multiply
   21,290x = 43,640 × 43,640
4. Step 4: Simplify right side
   21,290x = 1,904,449,600
5. Step 5: Solve for x
   x = 1,904,449,600/21,290
6. Step 6: Final answer
   x = 89,452.78