Finding the Fourth Proportional to 21,345, 29,457.72 and 12,963.12

Step by Step Solution

1. Step 1: Write the proportion equation
   21,345 : 29,457.72 = 12,963.12 : x
2. Step 2: Convert to fraction form
   21,345/29,457.72 = 12,963.12/x
3. Step 3: Cross multiply
   21,345x = 29,457.72 × 12,963.12
4. Step 4: Simplify right side
   21,345x = 381,863,959.29
5. Step 5: Solve for x
   x = 381,863,959.29/21,345
6. Step 6: Final answer
   x = 17,890.09