Finding the Fourth Proportional to 21,407.21, 29,547.89 and 12,456.45

Step by Step Solution

1. Step 1: Write the proportion equation
   21,407.21 : 29,547.89 = 12,456.45 : x
2. Step 2: Convert to fraction form
   21,407.21/29,547.89 = 12,456.45/x
3. Step 3: Cross multiply
   21,407.21x = 29,547.89 × 12,456.45
4. Step 4: Simplify right side
   21,407.21x = 368,061,814.39
5. Step 5: Solve for x
   x = 368,061,814.39/21,407.21
6. Step 6: Final answer
   x = 17,193.36