Finding the Fourth Proportional to 21,404.80, 32,105.60 and 8,921.60

Step by Step Solution

1. Step 1: Write the proportion equation
   21,404.80 : 32,105.60 = 8,921.60 : x
2. Step 2: Convert to fraction form
   21,404.80/32,105.60 = 8,921.60/x
3. Step 3: Cross multiply
   21,404.80x = 32,105.60 × 8,921.60
4. Step 4: Simplify right side
   21,404.80x = 286,433,320.96
5. Step 5: Solve for x
   x = 286,433,320.96/21,404.80
6. Step 6: Final answer
   x = 13,381.73