Finding the Third Proportional to 16,896 and 21,990

Step by Step Solution

1. Step 1: Write the proportion equation
   16,896 : 21,990 = 21,990 : x
2. Step 2: Convert to fraction form
   16,896/21,990 = 21,990/x
3. Step 3: Cross multiply
   16,896x = 21,990 × 21,990
4. Step 4: Simplify right side
   16,896x = 483,560,100
5. Step 5: Solve for x
   x = 483,560,100/16,896
6. Step 6: Final answer
   x = 28,619.80