Finding the Fourth Proportional to 11,721, 17,581.72 and 5,479.30

Step by Step Solution

1. Step 1: Write the proportion equation
   11,721 : 17,581.72 = 5,479.30 : x
2. Step 2: Convert to fraction form
   11,721/17,581.72 = 5,479.30/x
3. Step 3: Cross multiply
   11,721x = 17,581.72 × 5,479.30
4. Step 4: Simplify right side
   11,721x = 96,335,518.40
5. Step 5: Solve for x
   x = 96,335,518.40/11,721
6. Step 6: Final answer
   x = 8,219.05