Finding the Fourth Proportional to 21,411.07, 29,559.18 and 12,915.33

Step by Step Solution

1. Step 1: Write the proportion equation
   21,411.07 : 29,559.18 = 12,915.33 : x
2. Step 2: Convert to fraction form
   21,411.07/29,559.18 = 12,915.33/x
3. Step 3: Cross multiply
   21,411.07x = 29,559.18 × 12,915.33
4. Step 4: Simplify right side
   21,411.07x = 381,766,499.65
5. Step 5: Solve for x
   x = 381,766,499.65/21,411.07
6. Step 6: Final answer
   x = 17,830.34