Finding the Fourth Proportional to 11,103.60, 15,322.20 and 9,920.88

Step by Step Solution

1. Step 1: Write the proportion equation
   11,103.60 : 15,322.20 = 9,920.88 : x
2. Step 2: Convert to fraction form
   11,103.60/15,322.20 = 9,920.88/x
3. Step 3: Cross multiply
   11,103.60x = 15,322.20 × 9,920.88
4. Step 4: Simplify right side
   11,103.60x = 152,009,707.54
5. Step 5: Solve for x
   x = 152,009,707.54/11,103.60
6. Step 6: Final answer
   x = 13,690.13