Finding the Third Proportional to 21,990 and 42,900

Step by Step Solution

1. Step 1: Write the proportion equation
   21,990 : 42,900 = 42,900 : x
2. Step 2: Convert to fraction form
   21,990/42,900 = 42,900/x
3. Step 3: Cross multiply
   21,990x = 42,900 × 42,900
4. Step 4: Simplify right side
   21,990x = 1,840,410,000
5. Step 5: Solve for x
   x = 1,840,410,000/21,990
6. Step 6: Final answer
   x = 83,693.04