Finding the Fourth Proportional to 21,003.64, 28,974.81 and 13,443.91

Step by Step Solution

1. Step 1: Write the proportion equation
   21,003.64 : 28,974.81 = 13,443.91 : x
2. Step 2: Convert to fraction form
   21,003.64/28,974.81 = 13,443.91/x
3. Step 3: Cross multiply
   21,003.64x = 28,974.81 × 13,443.91
4. Step 4: Simplify right side
   21,003.64x = 389,534,715.88
5. Step 5: Solve for x
   x = 389,534,715.88/21,003.64
6. Step 6: Final answer
   x = 18,546.06