Finding the Fourth Proportional to 21,003.71, 28,990.71 and 12,397.46

Step by Step Solution

1. Step 1: Write the proportion equation
   21,003.71 : 28,990.71 = 12,397.46 : x
2. Step 2: Convert to fraction form
   21,003.71/28,990.71 = 12,397.46/x
3. Step 3: Cross multiply
   21,003.71x = 28,990.71 × 12,397.46
4. Step 4: Simplify right side
   21,003.71x = 359,411,022.64
5. Step 5: Solve for x
   x = 359,411,022.64/21,003.71
6. Step 6: Final answer
   x = 17,111.79