Finding the Third Proportional to 10,240 and 20,890

Step by Step Solution

1. Step 1: Write the proportion equation
   10,240 : 20,890 = 20,890 : x
2. Step 2: Convert to fraction form
   10,240/20,890 = 20,890/x
3. Step 3: Cross multiply
   10,240x = 20,890 × 20,890
4. Step 4: Simplify right side
   10,240x = 436,392,100
5. Step 5: Solve for x
   x = 436,392,100/10,240
6. Step 6: Final answer
   x = 42,616.42