Finding the Fourth Proportional to 21,488.69, 29,653.82 and 11,928.55

Step by Step Solution

1. Step 1: Write the proportion equation
   21,488.69 : 29,653.82 = 11,928.55 : x
2. Step 2: Convert to fraction form
   21,488.69/29,653.82 = 11,928.55/x
3. Step 3: Cross multiply
   21,488.69x = 29,653.82 × 11,928.55
4. Step 4: Simplify right side
   21,488.69x = 353,727,074.56
5. Step 5: Solve for x
   x = 353,727,074.56/21,488.69
6. Step 6: Final answer
   x = 16,461.08