Finding the Fourth Proportional to 11,818.10, 17,729.69 and 3,920.20

Step by Step Solution

1. Step 1: Write the proportion equation
   11,818.10 : 17,729.69 = 3,920.20 : x
2. Step 2: Convert to fraction form
   11,818.10/17,729.69 = 3,920.20/x
3. Step 3: Cross multiply
   11,818.10x = 17,729.69 × 3,920.20
4. Step 4: Simplify right side
   11,818.10x = 69,503,866.81
5. Step 5: Solve for x
   x = 69,503,866.81/11,818.10
6. Step 6: Final answer
   x = 5,881.14