Finding the Fourth Proportional to 21,013.50, 28,998.72 and 11,581.86

Step by Step Solution

1. Step 1: Write the proportion equation
   21,013.50 : 28,998.72 = 11,581.86 : x
2. Step 2: Convert to fraction form
   21,013.50/28,998.72 = 11,581.86/x
3. Step 3: Cross multiply
   21,013.50x = 28,998.72 × 11,581.86
4. Step 4: Simplify right side
   21,013.50x = 335,859,115.22
5. Step 5: Solve for x
   x = 335,859,115.22/21,013.50
6. Step 6: Final answer
   x = 15,983.02