Finding the Fourth Proportional to 21,510.63, 29,678.60 and 12,893.31

Step by Step Solution

1. Step 1: Write the proportion equation
   21,510.63 : 29,678.60 = 12,893.31 : x
2. Step 2: Convert to fraction form
   21,510.63/29,678.60 = 12,893.31/x
3. Step 3: Cross multiply
   21,510.63x = 29,678.60 × 12,893.31
4. Step 4: Simplify right side
   21,510.63x = 382,655,422.40
5. Step 5: Solve for x
   x = 382,655,422.40/21,510.63
6. Step 6: Final answer
   x = 17,789.13