Finding the Fourth Proportional to 21,665.87, 29,897.46 and 12,590.42

Step by Step Solution

1. Step 1: Write the proportion equation
   21,665.87 : 29,897.46 = 12,590.42 : x
2. Step 2: Convert to fraction form
   21,665.87/29,897.46 = 12,590.42/x
3. Step 3: Cross multiply
   21,665.87x = 29,897.46 × 12,590.42
4. Step 4: Simplify right side
   21,665.87x = 376,421,578.33
5. Step 5: Solve for x
   x = 376,421,578.33/21,665.87
6. Step 6: Final answer
   x = 17,373.94