Finding the Fourth Proportional to 21,124.72, 31,677.36 and 11,890.72

Step by Step Solution

1. Step 1: Write the proportion equation
   21,124.72 : 31,677.36 = 11,890.72 : x
2. Step 2: Convert to fraction form
   21,124.72/31,677.36 = 11,890.72/x
3. Step 3: Cross multiply
   21,124.72x = 31,677.36 × 11,890.72
4. Step 4: Simplify right side
   21,124.72x = 376,666,618.10
5. Step 5: Solve for x
   x = 376,666,618.10/21,124.72
6. Step 6: Final answer
   x = 17,830.61