Finding the Fourth Proportional to 21,981.69, 30,340.23 and 12,555.72

Step by Step Solution

1. Step 1: Write the proportion equation
   21,981.69 : 30,340.23 = 12,555.72 : x
2. Step 2: Convert to fraction form
   21,981.69/30,340.23 = 12,555.72/x
3. Step 3: Cross multiply
   21,981.69x = 30,340.23 × 12,555.72
4. Step 4: Simplify right side
   21,981.69x = 380,943,432.62
5. Step 5: Solve for x
   x = 380,943,432.62/21,981.69
6. Step 6: Final answer
   x = 17,330.03