Finding the Fourth Proportional to 16,100.80, 21,805.20 and 16,100.80

Step by Step Solution

1. Step 1: Write the proportion equation
   16,100.80 : 21,805.20 = 16,100.80 : x
2. Step 2: Convert to fraction form
   16,100.80/21,805.20 = 16,100.80/x
3. Step 3: Cross multiply
   16,100.80x = 21,805.20 × 16,100.80
4. Step 4: Simplify right side
   16,100.80x = 351,081,164.16
5. Step 5: Solve for x
   x = 351,081,164.16/16,100.80
6. Step 6: Final answer
   x = 21,805.20