Finding the Third Proportional to 21,138 and 42,858

Step by Step Solution

1. Step 1: Write the proportion equation
   21,138 : 42,858 = 42,858 : x
2. Step 2: Convert to fraction form
   21,138/42,858 = 42,858/x
3. Step 3: Cross multiply
   21,138x = 42,858 × 42,858
4. Step 4: Simplify right side
   21,138x = 1,836,808,164
5. Step 5: Solve for x
   x = 1,836,808,164/21,138
6. Step 6: Final answer
   x = 86,896.02