Finding the Third Proportional to 21,078 and 42,885

Step by Step Solution

1. Step 1: Write the proportion equation
   21,078 : 42,885 = 42,885 : x
2. Step 2: Convert to fraction form
   21,078/42,885 = 42,885/x
3. Step 3: Cross multiply
   21,078x = 42,885 × 42,885
4. Step 4: Simplify right side
   21,078x = 1,839,123,225
5. Step 5: Solve for x
   x = 1,839,123,225/21,078
6. Step 6: Final answer
   x = 87,253.21