Finding the Fourth Proportional to 11,387.62, 17,105.71 and 10,721.80

Step by Step Solution

1. Step 1: Write the proportion equation
   11,387.62 : 17,105.71 = 10,721.80 : x
2. Step 2: Convert to fraction form
   11,387.62/17,105.71 = 10,721.80/x
3. Step 3: Cross multiply
   11,387.62x = 17,105.71 × 10,721.80
4. Step 4: Simplify right side
   11,387.62x = 183,404,001.48
5. Step 5: Solve for x
   x = 183,404,001.48/11,387.62
6. Step 6: Final answer
   x = 16,105.56