Finding the Fourth Proportional to 21,411.78, 29,547.42 and 11,980.34

Step by Step Solution

1. Step 1: Write the proportion equation
   21,411.78 : 29,547.42 = 11,980.34 : x
2. Step 2: Convert to fraction form
   21,411.78/29,547.42 = 11,980.34/x
3. Step 3: Cross multiply
   21,411.78x = 29,547.42 × 11,980.34
4. Step 4: Simplify right side
   21,411.78x = 353,988,137.72
5. Step 5: Solve for x
   x = 353,988,137.72/21,411.78
6. Step 6: Final answer
   x = 16,532.40